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Commit be69f70e authored by Jiri Kosina's avatar Jiri Kosina
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Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and... 

Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and 'for-4.7/livepatching-ppc64' into for-linus
parents f09d9086 5e4e3844 4d4fb97a
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Showing with 1739 additions and 236 deletions
Documentation/livepatch/livepatch.txt 0 → 100644
View file @ be69f70e
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Documentation/livepatch/module-elf-format.txt 0 → 100644
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MAINTAINERS
View file @ be69f70e
......@@ -6605,6 +6605,7 @@ F: kernel/livepatch/
F: include/linux/livepatch.h
F: arch/x86/include/asm/livepatch.h
F: arch/x86/kernel/livepatch.c
F: Documentation/livepatch/
F: Documentation/ABI/testing/sysfs-kernel-livepatch
F: samples/livepatch/
L: live-patching@vger.kernel.org
......
arch/powerpc/Kconfig
View file @ be69f70e
......@@ -94,6 +94,7 @@ config PPC
select OF_RESERVED_MEM
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS if MPROFILE_KERNEL
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select SYSCTL_EXCEPTION_TRACE
......@@ -158,6 +159,7 @@ config PPC
select ARCH_HAS_DEVMEM_IS_ALLOWED
select HAVE_ARCH_SECCOMP_FILTER
select ARCH_HAS_UBSAN_SANITIZE_ALL
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
......@@ -373,6 +375,24 @@ config PPC_TRANSACTIONAL_MEM
---help---
Support user-mode Transactional Memory on POWERPC.
config DISABLE_MPROFILE_KERNEL
bool "Disable use of mprofile-kernel for kernel tracing"
depends on PPC64 && CPU_LITTLE_ENDIAN
default y
help
Selecting this options disables use of the mprofile-kernel ABI for
kernel tracing. That will cause options such as live patching
(CONFIG_LIVEPATCH) which depend on CONFIG_DYNAMIC_FTRACE_WITH_REGS to
be disabled also.
If you have a toolchain which supports mprofile-kernel, then you can
enable this. Otherwise leave it disabled. If you're not sure, say
"N".
config MPROFILE_KERNEL
depends on PPC64 && CPU_LITTLE_ENDIAN
def_bool !DISABLE_MPROFILE_KERNEL
config IOMMU_HELPER
def_bool PPC64
......@@ -1087,3 +1107,5 @@ config PPC_LIB_RHEAP
bool
source "arch/powerpc/kvm/Kconfig"
source "kernel/livepatch/Kconfig"
arch/powerpc/Makefile
View file @ be69f70e
......@@ -133,6 +133,21 @@ else
CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
endif
ifdef CONFIG_MPROFILE_KERNEL
ifeq ($(shell $(srctree)/arch/powerpc/scripts/gcc-check-mprofile-kernel.sh $(CC) -I$(srctree)/include -D__KERNEL__),OK)
CC_FLAGS_FTRACE := -pg -mprofile-kernel
KBUILD_CPPFLAGS += -DCC_USING_MPROFILE_KERNEL
else
# If the user asked for mprofile-kernel but the toolchain doesn't
# support it, emit a warning and deliberately break the build later
# with mprofile-kernel-not-supported. We would prefer to make this an
# error right here, but then the user would never be able to run
# oldconfig to change their configuration.
$(warning Compiler does not support mprofile-kernel, set CONFIG_DISABLE_MPROFILE_KERNEL)
CC_FLAGS_FTRACE := -mprofile-kernel-not-supported
endif
endif
CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
CFLAGS-$(CONFIG_POWER4_CPU) += $(call cc-option,-mcpu=power4)
CFLAGS-$(CONFIG_POWER5_CPU) += $(call cc-option,-mcpu=power5)
......
arch/powerpc/include/asm/code-patching.h
View file @ be69f70e
......@@ -99,4 +99,25 @@ static inline unsigned long ppc_global_function_entry(void *func)
#endif
}
#ifdef CONFIG_PPC64
/*
* Some instruction encodings commonly used in dynamic ftracing
* and function live patching.
*/
/* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
#if defined(_CALL_ELF) && _CALL_ELF == 2
#define R2_STACK_OFFSET 24
#else
#define R2_STACK_OFFSET 40
#endif
#define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
/* usually preceded by a mflr r0 */
#define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
#endif /* CONFIG_PPC64 */
#endif /* _ASM_POWERPC_CODE_PATCHING_H */
arch/powerpc/include/asm/ftrace.h
View file @ be69f70e
......@@ -46,6 +46,8 @@
extern void _mcount(void);
#ifdef CONFIG_DYNAMIC_FTRACE
# define FTRACE_ADDR ((unsigned long)ftrace_caller)
# define FTRACE_REGS_ADDR FTRACE_ADDR
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
/* reloction of mcount call site is the same as the address */
......@@ -58,6 +60,9 @@ struct dyn_arch_ftrace {
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
#define ARCH_SUPPORTS_FTRACE_OPS 1
#endif
#endif
#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) && !defined(__ASSEMBLY__)
......
arch/x86/kernel/livepatch.c → arch/powerpc/include/asm/livepatch.h
View file @ be69f70e
/*
* livepatch.c - x86-specific Kernel Live Patching Core
* livepatch.h - powerpc-specific Kernel Live Patching Core
*
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
* Copyright (C) 2014 SUSE
* Copyright (C) 2015-2016, SUSE, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
......@@ -17,54 +16,47 @@
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _ASM_POWERPC_LIVEPATCH_H
#define _ASM_POWERPC_LIVEPATCH_H
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/elf.h>
#include <asm/livepatch.h>
#include <linux/ftrace.h>
/**
* klp_write_module_reloc() - write a relocation in a module
* @mod: module in which the section to be modified is found
* @type: ELF relocation type (see asm/elf.h)
* @loc: address that the relocation should be written to
* @value: relocation value (sym address + addend)
*
* This function writes a relocation to the specified location for
* a particular module.
*/
int klp_write_module_reloc(struct module *mod, unsigned long type,
unsigned long loc, unsigned long value)
#ifdef CONFIG_LIVEPATCH
static inline int klp_check_compiler_support(void)
{
return 0;
}
static inline int klp_write_module_reloc(struct module *mod, unsigned long
type, unsigned long loc, unsigned long value)
{
size_t size = 4;
unsigned long val;
unsigned long core = (unsigned long)mod->core_layout.base;
unsigned long core_size = mod->core_layout.size;
/* This requires infrastructure changes; we need the loadinfos. */
return -ENOSYS;
}
switch (type) {
case R_X86_64_NONE:
return 0;
case R_X86_64_64:
val = value;
size = 8;
break;
case R_X86_64_32:
val = (u32)value;
break;
case R_X86_64_32S:
val = (s32)value;
break;
case R_X86_64_PC32:
val = (u32)(value - loc);
break;
default:
/* unsupported relocation type */
return -EINVAL;
}
static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
regs->nip = ip;
}
if (loc < core || loc >= core + core_size)
/* loc does not point to any symbol inside the module */
return -EINVAL;
#define klp_get_ftrace_location klp_get_ftrace_location
static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
{
/*
* Live patch works only with -mprofile-kernel on PPC. In this case,
* the ftrace location is always within the first 16 bytes.
*/
return ftrace_location_range(faddr, faddr + 16);
}
return probe_kernel_write((void *)loc, &val, size);
static inline void klp_init_thread_info(struct thread_info *ti)
{
/* + 1 to account for STACK_END_MAGIC */
ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
}
#else
static void klp_init_thread_info(struct thread_info *ti) { }
#endif /* CONFIG_LIVEPATCH */
#endif /* _ASM_POWERPC_LIVEPATCH_H */
arch/powerpc/include/asm/module.h
View file @ be69f70e
......@@ -78,10 +78,18 @@ struct mod_arch_specific {
# endif /* MODULE */
#endif
bool is_module_trampoline(u32 *insns);
int module_trampoline_target(struct module *mod, u32 *trampoline,
int module_trampoline_target(struct module *mod, unsigned long trampoline,
unsigned long *target);
#ifdef CONFIG_DYNAMIC_FTRACE
int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs);
#else
static inline int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
{
return 0;
}
#endif
struct exception_table_entry;
void sort_ex_table(struct exception_table_entry *start,
struct exception_table_entry *finish);
......
arch/powerpc/include/asm/sections.h
View file @ be69f70e
......@@ -22,6 +22,18 @@ static inline int in_kernel_text(unsigned long addr)
return 0;
}
static inline unsigned long kernel_toc_addr(void)
{
/* Defined by the linker, see vmlinux.lds.S */
extern unsigned long __toc_start;
/*
* The TOC register (r2) points 32kB into the TOC, so that 64kB of
* the TOC can be addressed using a single machine instruction.
*/
return (unsigned long)(&__toc_start) + 0x8000UL;
}
static inline int overlaps_interrupt_vector_text(unsigned long start,
unsigned long end)
{
......
arch/powerpc/include/asm/thread_info.h
View file @ be69f70e
......@@ -43,7 +43,9 @@ struct thread_info {
int preempt_count; /* 0 => preemptable,
<0 => BUG */
unsigned long local_flags; /* private flags for thread */
#ifdef CONFIG_LIVEPATCH
unsigned long *livepatch_sp;
#endif
/* low level flags - has atomic operations done on it */
unsigned long flags ____cacheline_aligned_in_smp;
};
......
arch/powerpc/kernel/Makefile
View file @ be69f70e
......@@ -16,14 +16,14 @@ endif
ifdef CONFIG_FUNCTION_TRACER
# Do not trace early boot code
CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_prom.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_cputable.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_prom_init.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_btext.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_prom.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
# do not trace tracer code
CFLAGS_REMOVE_ftrace.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_ftrace.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
# timers used by tracing
CFLAGS_REMOVE_time.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_time.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
endif
obj-y := cputable.o ptrace.o syscalls.o \
......
arch/powerpc/kernel/asm-offsets.c
View file @ be69f70e
......@@ -86,6 +86,10 @@ int main(void)
DEFINE(KSP_LIMIT, offsetof(struct thread_struct, ksp_limit));
#endif /* CONFIG_PPC64 */
#ifdef CONFIG_LIVEPATCH
DEFINE(TI_livepatch_sp, offsetof(struct thread_info, livepatch_sp));
#endif
DEFINE(KSP, offsetof(struct thread_struct, ksp));
DEFINE(PT_REGS, offsetof(struct thread_struct, regs));
#ifdef CONFIG_BOOKE
......
arch/powerpc/kernel/entry_64.S
View file @ be69f70e
......@@ -20,6 +20,7 @@
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/magic.h>
#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/page.h>
......@@ -1143,8 +1144,12 @@ _GLOBAL(enter_prom)
#ifdef CONFIG_DYNAMIC_FTRACE
_GLOBAL(mcount)
_GLOBAL(_mcount)
blr
mflr r12
mtctr r12
mtlr r0
bctr
#ifndef CC_USING_MPROFILE_KERNEL
_GLOBAL_TOC(ftrace_caller)
/* Taken from output of objdump from lib64/glibc */
mflr r3
......@@ -1166,8 +1171,213 @@ _GLOBAL(ftrace_graph_stub)
ld r0, 128(r1)
mtlr r0
addi r1, r1, 112
#else /* CC_USING_MPROFILE_KERNEL */
/*
*
* ftrace_caller() is the function that replaces _mcount() when ftrace is
* active.
*
* We arrive here after a function A calls function B, and we are the trace
* function for B. When we enter r1 points to A's stack frame, B has not yet
* had a chance to allocate one yet.
*
* Additionally r2 may point either to the TOC for A, or B, depending on
* whether B did a TOC setup sequence before calling us.
*
* On entry the LR points back to the _mcount() call site, and r0 holds the
* saved LR as it was on entry to B, ie. the original return address at the
* call site in A.
*
* Our job is to save the register state into a struct pt_regs (on the stack)
* and then arrange for the ftrace function to be called.
*/
_GLOBAL(ftrace_caller)
/* Save the original return address in A's stack frame */
std r0,LRSAVE(r1)
/* Create our stack frame + pt_regs */
stdu r1,-SWITCH_FRAME_SIZE(r1)
/* Save all gprs to pt_regs */
SAVE_8GPRS(0,r1)
SAVE_8GPRS(8,r1)
SAVE_8GPRS(16,r1)
SAVE_8GPRS(24,r1)
/* Load special regs for save below */
mfmsr r8
mfctr r9
mfxer r10
mfcr r11
/* Get the _mcount() call site out of LR */
mflr r7
/* Save it as pt_regs->nip & pt_regs->link */
std r7, _NIP(r1)
std r7, _LINK(r1)
/* Save callee's TOC in the ABI compliant location */
std r2, 24(r1)
ld r2,PACATOC(r13) /* get kernel TOC in r2 */
addis r3,r2,function_trace_op@toc@ha
addi r3,r3,function_trace_op@toc@l
ld r5,0(r3)
#ifdef CONFIG_LIVEPATCH
mr r14,r7 /* remember old NIP */
#endif
/* Calculate ip from nip-4 into r3 for call below */
subi r3, r7, MCOUNT_INSN_SIZE
/* Put the original return address in r4 as parent_ip */
mr r4, r0
/* Save special regs */
std r8, _MSR(r1)
std r9, _CTR(r1)
std r10, _XER(r1)
std r11, _CCR(r1)
/* Load &pt_regs in r6 for call below */
addi r6, r1 ,STACK_FRAME_OVERHEAD
/* ftrace_call(r3, r4, r5, r6) */
.globl ftrace_call
ftrace_call:
bl ftrace_stub
nop
/* Load ctr with the possibly modified NIP */
ld r3, _NIP(r1)
mtctr r3
#ifdef CONFIG_LIVEPATCH
cmpd r14,r3 /* has NIP been altered? */
#endif
/* Restore gprs */
REST_8GPRS(0,r1)
REST_8GPRS(8,r1)
REST_8GPRS(16,r1)
REST_8GPRS(24,r1)
/* Restore callee's TOC */
ld r2, 24(r1)
/* Pop our stack frame */
addi r1, r1, SWITCH_FRAME_SIZE
/* Restore original LR for return to B */
ld r0, LRSAVE(r1)
mtlr r0
#ifdef CONFIG_LIVEPATCH
/* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
stdu r1, -112(r1)
.globl ftrace_graph_call
ftrace_graph_call:
b ftrace_graph_stub
_GLOBAL(ftrace_graph_stub)
addi r1, r1, 112
#endif
ld r0,LRSAVE(r1) /* restore callee's lr at _mcount site */
mtlr r0
bctr /* jump after _mcount site */
#endif /* CC_USING_MPROFILE_KERNEL */
_GLOBAL(ftrace_stub)
blr
#ifdef CONFIG_LIVEPATCH
/*
* This function runs in the mcount context, between two functions. As
* such it can only clobber registers which are volatile and used in
* function linkage.
*
* We get here when a function A, calls another function B, but B has
* been live patched with a new function C.
*
* On entry:
* - we have no stack frame and can not allocate one
* - LR points back to the original caller (in A)
* - CTR holds the new NIP in C
* - r0 & r12 are free
*
* r0 can't be used as the base register for a DS-form load or store, so
* we temporarily shuffle r1 (stack pointer) into r0 and then put it back.
*/
livepatch_handler:
CURRENT_THREAD_INFO(r12, r1)
/* Save stack pointer into r0 */
mr r0, r1
/* Allocate 3 x 8 bytes */
ld r1, TI_livepatch_sp(r12)
addi r1, r1, 24
std r1, TI_livepatch_sp(r12)
/* Save toc & real LR on livepatch stack */
std r2, -24(r1)
mflr r12
std r12, -16(r1)
/* Store stack end marker */
lis r12, STACK_END_MAGIC@h
ori r12, r12, STACK_END_MAGIC@l
std r12, -8(r1)
/* Restore real stack pointer */
mr r1, r0
/* Put ctr in r12 for global entry and branch there */
mfctr r12
bctrl
/*
* Now we are returning from the patched function to the original
* caller A. We are free to use r0 and r12, and we can use r2 until we
* restore it.
*/
CURRENT_THREAD_INFO(r12, r1)
/* Save stack pointer into r0 */
mr r0, r1
ld r1, TI_livepatch_sp(r12)
/* Check stack marker hasn't been trashed */
lis r2, STACK_END_MAGIC@h
ori r2, r2, STACK_END_MAGIC@l
ld r12, -8(r1)
1: tdne r12, r2
EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0
/* Restore LR & toc from livepatch stack */
ld r12, -16(r1)
mtlr r12
ld r2, -24(r1)
/* Pop livepatch stack frame */
CURRENT_THREAD_INFO(r12, r0)
subi r1, r1, 24
std r1, TI_livepatch_sp(r12)
/* Restore real stack pointer */
mr r1, r0
/* Return to original caller of live patched function */
blr
#endif
#else
_GLOBAL_TOC(_mcount)
/* Taken from output of objdump from lib64/glibc */
......@@ -1198,6 +1408,7 @@ _GLOBAL(ftrace_stub)
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#ifndef CC_USING_MPROFILE_KERNEL
_GLOBAL(ftrace_graph_caller)
/* load r4 with local address */
ld r4, 128(r1)
......@@ -1222,6 +1433,56 @@ _GLOBAL(ftrace_graph_caller)
addi r1, r1, 112
blr
#else /* CC_USING_MPROFILE_KERNEL */
_GLOBAL(ftrace_graph_caller)
/* with -mprofile-kernel, parameter regs are still alive at _mcount */
std r10, 104(r1)
std r9, 96(r1)
std r8, 88(r1)
std r7, 80(r1)
std r6, 72(r1)
std r5, 64(r1)
std r4, 56(r1)
std r3, 48(r1)
/* Save callee's TOC in the ABI compliant location */
std r2, 24(r1)
ld r2, PACATOC(r13) /* get kernel TOC in r2 */
mfctr r4 /* ftrace_caller has moved local addr here */
std r4, 40(r1)
mflr r3 /* ftrace_caller has restored LR from stack */
subi r4, r4, MCOUNT_INSN_SIZE
bl prepare_ftrace_return
nop
/*
* prepare_ftrace_return gives us the address we divert to.
* Change the LR to this.
*/
mtlr r3
ld r0, 40(r1)
mtctr r0
ld r10, 104(r1)
ld r9, 96(r1)
ld r8, 88(r1)
ld r7, 80(r1)
ld r6, 72(r1)
ld r5, 64(r1)
ld r4, 56(r1)
ld r3, 48(r1)
/* Restore callee's TOC */
ld r2, 24(r1)
addi r1, r1, 112
mflr r0
std r0, LRSAVE(r1)
bctr
#endif /* CC_USING_MPROFILE_KERNEL */
_GLOBAL(return_to_handler)
/* need to save return values */
std r4, -32(r1)
......
arch/powerpc/kernel/ftrace.c
View file @ be69f70e
......@@ -61,8 +61,11 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
return -EFAULT;
/* Make sure it is what we expect it to be */
if (replaced != old)
if (replaced != old) {
pr_err("%p: replaced (%#x) != old (%#x)",
(void *)ip, replaced, old);
return -EINVAL;
}
/* replace the text with the new text */
if (patch_instruction((unsigned int *)ip, new))
......@@ -106,14 +109,15 @@ static int
__ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr)
{
unsigned int op;
unsigned long entry, ptr;
unsigned long entry, ptr, tramp;
unsigned long ip = rec->ip;
void *tramp;
unsigned int op, pop;
/* read where this goes */
if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
pr_err("Fetching opcode failed.\n");
return -EFAULT;
}
/* Make sure that that this is still a 24bit jump */
if (!is_bl_op(op)) {
......@@ -122,14 +126,9 @@ __ftrace_make_nop(struct module *mod,
}
/* lets find where the pointer goes */
tramp = (void *)find_bl_target(ip, op);
pr_devel("ip:%lx jumps to %p", ip, tramp);
tramp = find_bl_target(ip, op);
if (!is_module_trampoline(tramp)) {
pr_err("Not a trampoline\n");
return -EINVAL;
}
pr_devel("ip:%lx jumps to %lx", ip, tramp);
if (module_trampoline_target(mod, tramp, &ptr)) {
pr_err("Failed to get trampoline target\n");
......@@ -158,10 +157,42 @@ __ftrace_make_nop(struct module *mod,
*
* Use a b +8 to jump over the load.
*/
op = 0x48000008; /* b +8 */
if (patch_instruction((unsigned int *)ip, op))
pop = PPC_INST_BRANCH | 8; /* b +8 */
/*
* Check what is in the next instruction. We can see ld r2,40(r1), but
* on first pass after boot we will see mflr r0.
*/
if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) {
pr_err("Fetching op failed.\n");
return -EFAULT;
}
if (op != PPC_INST_LD_TOC) {
unsigned int inst;
if (probe_kernel_read(&inst, (void *)(ip - 4), 4)) {
pr_err("Fetching instruction at %lx failed.\n", ip - 4);
return -EFAULT;
}
/* We expect either a mlfr r0, or a std r0, LRSAVE(r1) */
if (inst != PPC_INST_MFLR && inst != PPC_INST_STD_LR) {
pr_err("Unexpected instructions around bl _mcount\n"
"when enabling dynamic ftrace!\t"
"(%08x,bl,%08x)\n", inst, op);
return -EINVAL;
}
/* When using -mkernel_profile there is no load to jump over */
pop = PPC_INST_NOP;
}
if (patch_instruction((unsigned int *)ip, pop)) {
pr_err("Patching NOP failed.\n");
return -EPERM;
}
return 0;
}
......@@ -287,16 +318,15 @@ int ftrace_make_nop(struct module *mod,
#ifdef CONFIG_MODULES
#ifdef CONFIG_PPC64
/*
* Examine the existing instructions for __ftrace_make_call.
* They should effectively be a NOP, and follow formal constraints,
* depending on the ABI. Return false if they don't.
*/
#ifndef CC_USING_MPROFILE_KERNEL
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1)
{
unsigned int op[2];
void *ip = (void *)rec->ip;
/* read where this goes */
if (probe_kernel_read(op, ip, sizeof(op)))
return -EFAULT;
/*
* We expect to see:
*
......@@ -306,8 +336,34 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* The load offset is different depending on the ABI. For simplicity
* just mask it out when doing the compare.
*/
if ((op[0] != 0x48000008) || ((op[1] & 0xffff0000) != 0xe8410000)) {
pr_err("Unexpected call sequence: %x %x\n", op[0], op[1]);
if ((op0 != 0x48000008) || ((op1 & 0xffff0000) != 0xe8410000))
return 0;
return 1;
}
#else
static int
expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1)
{
/* look for patched "NOP" on ppc64 with -mprofile-kernel */
if (op0 != PPC_INST_NOP)
return 0;
return 1;
}
#endif
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
unsigned int op[2];
void *ip = (void *)rec->ip;
/* read where this goes */
if (probe_kernel_read(op, ip, sizeof(op)))
return -EFAULT;
if (!expected_nop_sequence(ip, op[0], op[1])) {
pr_err("Unexpected call sequence at %p: %x %x\n",
ip, op[0], op[1]);
return -EINVAL;
}
......@@ -330,7 +386,16 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return 0;
}
#else
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
return ftrace_make_call(rec, addr);
}
#endif
#else /* !CONFIG_PPC64: */
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
......@@ -455,20 +520,13 @@ void ftrace_replace_code(int enable)
}
}
/*
* Use the default ftrace_modify_all_code, but without
* stop_machine().
*/
void arch_ftrace_update_code(int command)
{
if (command & FTRACE_UPDATE_CALLS)
ftrace_replace_code(1);
else if (command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(0);
if (command & FTRACE_UPDATE_TRACE_FUNC)
ftrace_update_ftrace_func(ftrace_trace_function);
if (command & FTRACE_START_FUNC_RET)
ftrace_enable_ftrace_graph_caller();
else if (command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
ftrace_modify_all_code(command);
}
int __init ftrace_dyn_arch_init(void)
......
arch/powerpc/kernel/irq.c
View file @ be69f70e
......@@ -66,6 +66,7 @@
#include <asm/udbg.h>
#include <asm/smp.h>
#include <asm/debug.h>
#include <asm/livepatch.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
......@@ -607,10 +608,12 @@ void irq_ctx_init(void)
memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
tp = softirq_ctx[i];
tp->cpu = i;
klp_init_thread_info(tp);
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
klp_init_thread_info(tp);
}
}
......
arch/powerpc/kernel/module.c
View file @ be69f70e
......@@ -47,6 +47,11 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *me)
{
const Elf_Shdr *sect;
int rc;
rc = module_finalize_ftrace(me, sechdrs);
if (rc)
return rc;
/* Apply feature fixups */
sect = find_section(hdr, sechdrs, "__ftr_fixup");
......
arch/powerpc/kernel/module_32.c
View file @ be69f70e
......@@ -181,7 +181,7 @@ static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
/* Set up a trampoline in the PLT to bounce us to the distant function */
static uint32_t do_plt_call(void *location,
Elf32_Addr val,
Elf32_Shdr *sechdrs,
const Elf32_Shdr *sechdrs,
struct module *mod)
{
struct ppc_plt_entry *entry;
......@@ -294,11 +294,19 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
return -ENOEXEC;
}
}
return 0;
}
#ifdef CONFIG_DYNAMIC_FTRACE
module->arch.tramp =
do_plt_call(module->core_layout.base,
(unsigned long)ftrace_caller,
sechdrs, module);
#endif
int module_finalize_ftrace(struct module *module, const Elf_Shdr *sechdrs)
{
module->arch.tramp = do_plt_call(module->core_layout.base,
(unsigned long)ftrace_caller,
sechdrs, module);
if (!module->arch.tramp)
return -ENOENT;
return 0;
}
#endif
arch/powerpc/kernel/module_64.c
View file @ be69f70e
......@@ -31,6 +31,7 @@
#include <asm/code-patching.h>
#include <linux/sort.h>
#include <asm/setup.h>
#include <asm/sections.h>
/* FIXME: We don't do .init separately. To do this, we'd need to have
a separate r2 value in the init and core section, and stub between
......@@ -41,7 +42,6 @@
--RR. */
#if defined(_CALL_ELF) && _CALL_ELF == 2
#define R2_STACK_OFFSET 24
/* An address is simply the address of the function. */
typedef unsigned long func_desc_t;
......@@ -73,7 +73,6 @@ static unsigned int local_entry_offset(const Elf64_Sym *sym)
return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
}
#else
#define R2_STACK_OFFSET 40
/* An address is address of the OPD entry, which contains address of fn. */
typedef struct ppc64_opd_entry func_desc_t;
......@@ -96,6 +95,8 @@ static unsigned int local_entry_offset(const Elf64_Sym *sym)
}
#endif
#define STUB_MAGIC 0x73747562 /* stub */
/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
the kernel itself). But on PPC64, these need to be used for every
jump, actually, to reset r2 (TOC+0x8000). */
......@@ -105,7 +106,8 @@ struct ppc64_stub_entry
* need 6 instructions on ABIv2 but we always allocate 7 so
* so we don't have to modify the trampoline load instruction. */
u32 jump[7];
u32 unused;
/* Used by ftrace to identify stubs */
u32 magic;
/* Data for the above code */
func_desc_t funcdata;
};
......@@ -139,70 +141,39 @@ static u32 ppc64_stub_insns[] = {
};
#ifdef CONFIG_DYNAMIC_FTRACE
static u32 ppc64_stub_mask[] = {
0xffff0000,
0xffff0000,
0xffffffff,
0xffffffff,
#if !defined(_CALL_ELF) || _CALL_ELF != 2
0xffffffff,
#endif
0xffffffff,
0xffffffff
};
bool is_module_trampoline(u32 *p)
int module_trampoline_target(struct module *mod, unsigned long addr,
unsigned long *target)
{
unsigned int i;
u32 insns[ARRAY_SIZE(ppc64_stub_insns)];
BUILD_BUG_ON(sizeof(ppc64_stub_insns) != sizeof(ppc64_stub_mask));
struct ppc64_stub_entry *stub;
func_desc_t funcdata;
u32 magic;
if (probe_kernel_read(insns, p, sizeof(insns)))
if (!within_module_core(addr, mod)) {
pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
u32 insna = insns[i];
u32 insnb = ppc64_stub_insns[i];
u32 mask = ppc64_stub_mask[i];
if ((insna & mask) != (insnb & mask))
return false;
}
return true;
}
int module_trampoline_target(struct module *mod, u32 *trampoline,
unsigned long *target)
{
u32 buf[2];
u16 upper, lower;
long offset;
void *toc_entry;
stub = (struct ppc64_stub_entry *)addr;
if (probe_kernel_read(buf, trampoline, sizeof(buf)))
if (probe_kernel_read(&magic, &stub->magic, sizeof(magic))) {
pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
return -EFAULT;
}
upper = buf[0] & 0xffff;
lower = buf[1] & 0xffff;
/* perform the addis/addi, both signed */
offset = ((short)upper << 16) + (short)lower;
if (magic != STUB_MAGIC) {
pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
return -EFAULT;
}
/*
* Now get the address this trampoline jumps to. This
* is always 32 bytes into our trampoline stub.
*/
toc_entry = (void *)mod->arch.toc + offset + 32;
if (probe_kernel_read(&funcdata, &stub->funcdata, sizeof(funcdata))) {
pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
return -EFAULT;
}
if (probe_kernel_read(target, toc_entry, sizeof(*target)))
return -EFAULT;
*target = stub_func_addr(funcdata);
return 0;
}
#endif
/* Count how many different 24-bit relocations (different symbol,
......@@ -413,7 +384,7 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
/* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this
gives the value maximum span in an instruction which uses a signed
offset) */
static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me)
static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
{
return sechdrs[me->arch.toc_section].sh_addr + 0x8000;
}
......@@ -426,7 +397,7 @@ static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me)
#define PPC_HA(v) PPC_HI ((v) + 0x8000)
/* Patch stub to reference function and correct r2 value. */
static inline int create_stub(Elf64_Shdr *sechdrs,
static inline int create_stub(const Elf64_Shdr *sechdrs,
struct ppc64_stub_entry *entry,
unsigned long addr,
struct module *me)
......@@ -447,12 +418,14 @@ static inline int create_stub(Elf64_Shdr *sechdrs,
entry->jump[0] |= PPC_HA(reladdr);
entry->jump[1] |= PPC_LO(reladdr);
entry->funcdata = func_desc(addr);
entry->magic = STUB_MAGIC;
return 1;
}
/* Create stub to jump to function described in this OPD/ptr: we need the
stub to set up the TOC ptr (r2) for the function. */
static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
unsigned long addr,
struct module *me)
{
......@@ -476,17 +449,60 @@ static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
return (unsigned long)&stubs[i];
}
#ifdef CC_USING_MPROFILE_KERNEL
static bool is_early_mcount_callsite(u32 *instruction)
{
/*
* Check if this is one of the -mprofile-kernel sequences.
*/
if (instruction[-1] == PPC_INST_STD_LR &&
instruction[-2] == PPC_INST_MFLR)
return true;
if (instruction[-1] == PPC_INST_MFLR)
return true;
return false;
}
/*
* In case of _mcount calls, do not save the current callee's TOC (in r2) into
* the original caller's stack frame. If we did we would clobber the saved TOC
* value of the original caller.
*/
static void squash_toc_save_inst(const char *name, unsigned long addr)
{
struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr;
/* Only for calls to _mcount */
if (strcmp("_mcount", name) != 0)
return;
stub->jump[2] = PPC_INST_NOP;
}
#else
static void squash_toc_save_inst(const char *name, unsigned long addr) { }
/* without -mprofile-kernel, mcount calls are never early */
static bool is_early_mcount_callsite(u32 *instruction)
{
return false;
}
#endif
/* We expect a noop next: if it is, replace it with instruction to
restore r2. */
static int restore_r2(u32 *instruction, struct module *me)
{
if (*instruction != PPC_INST_NOP) {
if (is_early_mcount_callsite(instruction - 1))
return 1;
pr_err("%s: Expect noop after relocate, got %08x\n",
me->name, *instruction);
return 0;
}
/* ld r2,R2_STACK_OFFSET(r1) */
*instruction = 0xe8410000 | R2_STACK_OFFSET;
*instruction = PPC_INST_LD_TOC;
return 1;
}
......@@ -611,6 +627,8 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
return -ENOENT;
if (!restore_r2((u32 *)location + 1, me))
return -ENOEXEC;
squash_toc_save_inst(strtab + sym->st_name, value);
} else
value += local_entry_offset(sym);
......@@ -693,12 +711,84 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
}
}
return 0;
}
#ifdef CONFIG_DYNAMIC_FTRACE
me->arch.toc = my_r2(sechdrs, me);
me->arch.tramp = stub_for_addr(sechdrs,
(unsigned long)ftrace_caller,
me);
#ifdef CC_USING_MPROFILE_KERNEL
#define PACATOC offsetof(struct paca_struct, kernel_toc)
/*
* For mprofile-kernel we use a special stub for ftrace_caller() because we
* can't rely on r2 containing this module's TOC when we enter the stub.
*
* That can happen if the function calling us didn't need to use the toc. In
* that case it won't have setup r2, and the r2 value will be either the
* kernel's toc, or possibly another modules toc.
*
* To deal with that this stub uses the kernel toc, which is always accessible
* via the paca (in r13). The target (ftrace_caller()) is responsible for
* saving and restoring the toc before returning.
*/
static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs, struct module *me)
{
struct ppc64_stub_entry *entry;
unsigned int i, num_stubs;
static u32 stub_insns[] = {
0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
0x3d8c0000, /* addis r12,r12,<high> */
0x398c0000, /* addi r12,r12,<low> */
0x7d8903a6, /* mtctr r12 */
0x4e800420, /* bctr */
};
long reladdr;
num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*entry);
/* Find the next available stub entry */
entry = (void *)sechdrs[me->arch.stubs_section].sh_addr;
for (i = 0; i < num_stubs && stub_func_addr(entry->funcdata); i++, entry++);
if (i >= num_stubs) {
pr_err("%s: Unable to find a free slot for ftrace stub.\n", me->name);
return 0;
}
memcpy(entry->jump, stub_insns, sizeof(stub_insns));
/* Stub uses address relative to kernel toc (from the paca) */
reladdr = (unsigned long)ftrace_caller - kernel_toc_addr();
if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
pr_err("%s: Address of ftrace_caller out of range of kernel_toc.\n", me->name);
return 0;
}
entry->jump[1] |= PPC_HA(reladdr);
entry->jump[2] |= PPC_LO(reladdr);
/* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */
entry->funcdata = func_desc((unsigned long)ftrace_caller);
entry->magic = STUB_MAGIC;
return (unsigned long)entry;
}
#else
static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs, struct module *me)
{
return stub_for_addr(sechdrs, (unsigned long)ftrace_caller, me);
}
#endif
int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
{
mod->arch.toc = my_r2(sechdrs, mod);
mod->arch.tramp = create_ftrace_stub(sechdrs, mod);
if (!mod->arch.tramp)
return -ENOENT;
return 0;
}
#endif
arch/powerpc/kernel/paca.c
View file @ be69f70e
......@@ -17,10 +17,6 @@
#include <asm/pgtable.h>
#include <asm/kexec.h>
/* This symbol is provided by the linker - let it fill in the paca
* field correctly */
extern unsigned long __toc_start;
#ifdef CONFIG_PPC_BOOK3S
/*
......@@ -149,11 +145,6 @@ EXPORT_SYMBOL(paca);
void __init initialise_paca(struct paca_struct *new_paca, int cpu)
{
/* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
* of the TOC can be addressed using a single machine instruction.
*/
unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
#ifdef CONFIG_PPC_BOOK3S
new_paca->lppaca_ptr = new_lppaca(cpu);
#else
......@@ -161,7 +152,7 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu)
#endif
new_paca->lock_token = 0x8000;
new_paca->paca_index = cpu;
new_paca->kernel_toc = kernel_toc;
new_paca->kernel_toc = kernel_toc_addr();
new_paca->kernelbase = (unsigned long) _stext;
/* Only set MSR:IR/DR when MMU is initialized */
new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
......
arch/powerpc/kernel/process.c
View file @ be69f70e
......@@ -55,6 +55,8 @@
#include <asm/firmware.h>
#endif
#include <asm/code-patching.h>
#include <asm/livepatch.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
......@@ -1267,13 +1269,15 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
struct thread_info *ti = task_thread_info(p);
klp_init_thread_info(ti);
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
struct thread_info *ti = (void *)task_stack_page(p);
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
......
arch/powerpc/kernel/setup_64.c
View file @ be69f70e
......@@ -69,6 +69,7 @@
#include <asm/kvm_ppc.h>
#include <asm/hugetlb.h>
#include <asm/epapr_hcalls.h>
#include <asm/livepatch.h>
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
......@@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
limit = min(safe_stack_limit(), ppc64_rma_size);
for_each_possible_cpu(i) {
unsigned long sp;
sp = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
sp += THREAD_SIZE;
paca[i].emergency_sp = __va(sp);
struct thread_info *ti;
ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
klp_init_thread_info(ti);
paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
#ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for machine check exception handling. */
sp = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
sp += THREAD_SIZE;
paca[i].mc_emergency_sp = __va(sp);
ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
klp_init_thread_info(ti);
paca[i].mc_emergency_sp = (void *)ti + THREAD_SIZE;
#endif
}
}
......@@ -700,6 +701,8 @@ void __init setup_arch(char **cmdline_p)
if (ppc_md.panic)
setup_panic();
klp_init_thread_info(&init_thread_info);
init_mm.start_code = (unsigned long)_stext;
init_mm.end_code = (unsigned long) _etext;
init_mm.end_data = (unsigned long) _edata;
......
arch/powerpc/lib/Makefile
View file @ be69f70e
......@@ -6,8 +6,8 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
CFLAGS_REMOVE_code-patching.o = -pg
CFLAGS_REMOVE_feature-fixups.o = -pg
CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)
obj-y += string.o alloc.o crtsavres.o ppc_ksyms.o code-patching.o \
feature-fixups.o
......
arch/powerpc/platforms/powermac/Makefile
View file @ be69f70e
......@@ -2,7 +2,7 @@ CFLAGS_bootx_init.o += -fPIC
ifdef CONFIG_FUNCTION_TRACER
# Do not trace early boot code
CFLAGS_REMOVE_bootx_init.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_bootx_init.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)
endif
obj-y += pic.o setup.o time.o feature.o pci.o \
......
arch/powerpc/scripts/gcc-check-mprofile-kernel.sh 0 → 100755
View file @ be69f70e
#!/bin/bash
set -e
set -o pipefail
# To debug, uncomment the following line
# set -x
# Test whether the compile option -mprofile-kernel exists and generates
# profiling code (ie. a call to _mcount()).
echo "int func() { return 0; }" | \
$* -S -x c -O2 -p -mprofile-kernel - -o - 2> /dev/null | \
grep -q "_mcount"
# Test whether the notrace attribute correctly suppresses calls to _mcount().
echo -e "#include <linux/compiler.h>\nnotrace int func() { return 0; }" | \
$* -S -x c -O2 -p -mprofile-kernel - -o - 2> /dev/null | \
grep -q "_mcount" && \
exit 1
echo "OK"
exit 0
arch/s390/include/asm/livepatch.h
View file @ be69f70e
......@@ -24,13 +24,6 @@ static inline int klp_check_compiler_support(void)
return 0;
}
static inline int klp_write_module_reloc(struct module *mod, unsigned long
type, unsigned long loc, unsigned long value)
{
/* not supported yet */
return -ENOSYS;
}
static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
regs->psw.addr = ip;
......
arch/s390/kernel/module.c
View file @ be69f70e
......@@ -51,6 +51,10 @@ void *module_alloc(unsigned long size)
void module_arch_freeing_init(struct module *mod)
{
if (is_livepatch_module(mod) &&
mod->state == MODULE_STATE_LIVE)
return;
vfree(mod->arch.syminfo);
mod->arch.syminfo = NULL;
}
......@@ -425,7 +429,5 @@ int module_finalize(const Elf_Ehdr *hdr,
struct module *me)
{
jump_label_apply_nops(me);
vfree(me->arch.syminfo);
me->arch.syminfo = NULL;
return 0;
}
arch/x86/include/asm/livepatch.h
View file @ be69f70e
......@@ -32,8 +32,6 @@ static inline int klp_check_compiler_support(void)
#endif
return 0;
}
int klp_write_module_reloc(struct module *mod, unsigned long type,
unsigned long loc, unsigned long value);
static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
......
arch/x86/kernel/Makefile
View file @ be69f70e
......@@ -67,7 +67,6 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o
obj-y += apic/
obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_LIVEPATCH) += livepatch.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_X86_TSC) += trace_clock.o
......
include/linux/ftrace.h
View file @ be69f70e
......@@ -455,6 +455,7 @@ int ftrace_update_record(struct dyn_ftrace *rec, int enable);
int ftrace_test_record(struct dyn_ftrace *rec, int enable);
void ftrace_run_stop_machine(int command);
unsigned long ftrace_location(unsigned long ip);
unsigned long ftrace_location_range(unsigned long start, unsigned long end);
unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
......
include/linux/livepatch.h
View file @ be69f70e
......@@ -64,28 +64,9 @@ struct klp_func {
struct list_head stack_node;
};
/**
* struct klp_reloc - relocation structure for live patching
* @loc: address where the relocation will be written
* @sympos: position in kallsyms to disambiguate symbols (optional)
* @type: ELF relocation type
* @name: name of the referenced symbol (for lookup/verification)
* @addend: offset from the referenced symbol
* @external: symbol is either exported or within the live patch module itself
*/
struct klp_reloc {
unsigned long loc;
unsigned long sympos;
unsigned long type;
const char *name;
int addend;
int external;
};
/**
* struct klp_object - kernel object structure for live patching
* @name: module name (or NULL for vmlinux)
* @relocs: relocation entries to be applied at load time
* @funcs: function entries for functions to be patched in the object
* @kobj: kobject for sysfs resources
* @mod: kernel module associated with the patched object
......@@ -95,7 +76,6 @@ struct klp_reloc {
struct klp_object {
/* external */
const char *name;
struct klp_reloc *relocs;
struct klp_func *funcs;
/* internal */
......
include/linux/module.h
View file @ be69f70e
......@@ -330,6 +330,15 @@ struct mod_kallsyms {
char *strtab;
};
#ifdef CONFIG_LIVEPATCH
struct klp_modinfo {
Elf_Ehdr hdr;
Elf_Shdr *sechdrs;
char *secstrings;
unsigned int symndx;
};
#endif
struct module {
enum module_state state;
......@@ -456,7 +465,11 @@ struct module {
#endif
#ifdef CONFIG_LIVEPATCH
bool klp; /* Is this a livepatch module? */
bool klp_alive;
/* Elf information */
struct klp_modinfo *klp_info;
#endif
#ifdef CONFIG_MODULE_UNLOAD
......@@ -630,6 +643,18 @@ static inline bool module_requested_async_probing(struct module *module)
return module && module->async_probe_requested;
}
#ifdef CONFIG_LIVEPATCH
static inline bool is_livepatch_module(struct module *mod)
{
return mod->klp;
}
#else /* !CONFIG_LIVEPATCH */
static inline bool is_livepatch_module(struct module *mod)
{
return false;
}
#endif /* CONFIG_LIVEPATCH */
#else /* !CONFIG_MODULES... */
/* Given an address, look for it in the exception tables. */
......
include/uapi/linux/elf.h
View file @ be69f70e
......@@ -282,16 +282,18 @@ typedef struct elf64_phdr {
#define SHT_HIUSER 0xffffffff
/* sh_flags */
#define SHF_WRITE 0x1
#define SHF_ALLOC 0x2
#define SHF_EXECINSTR 0x4
#define SHF_MASKPROC 0xf0000000
#define SHF_WRITE 0x1
#define SHF_ALLOC 0x2
#define SHF_EXECINSTR 0x4
#define SHF_RELA_LIVEPATCH 0x00100000
#define SHF_MASKPROC 0xf0000000
/* special section indexes */
#define SHN_UNDEF 0
#define SHN_LORESERVE 0xff00
#define SHN_LOPROC 0xff00
#define SHN_HIPROC 0xff1f
#define SHN_LIVEPATCH 0xff20
#define SHN_ABS 0xfff1
#define SHN_COMMON 0xfff2
#define SHN_HIRESERVE 0xffff
......
kernel/livepatch/core.c
View file @ be69f70e
......@@ -28,6 +28,8 @@
#include <linux/list.h>
#include <linux/kallsyms.h>
#include <linux/livepatch.h>
#include <linux/elf.h>
#include <linux/moduleloader.h>
#include <asm/cacheflush.h>
/**
......@@ -204,75 +206,109 @@ static int klp_find_object_symbol(const char *objname, const char *name,
return -EINVAL;
}
/*
* external symbols are located outside the parent object (where the parent
* object is either vmlinux or the kmod being patched).
*/
static int klp_find_external_symbol(struct module *pmod, const char *name,
unsigned long *addr)
static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
{
const struct kernel_symbol *sym;
/* first, check if it's an exported symbol */
preempt_disable();
sym = find_symbol(name, NULL, NULL, true, true);
if (sym) {
*addr = sym->value;
preempt_enable();
return 0;
}
preempt_enable();
int i, cnt, vmlinux, ret;
char objname[MODULE_NAME_LEN];
char symname[KSYM_NAME_LEN];
char *strtab = pmod->core_kallsyms.strtab;
Elf_Rela *relas;
Elf_Sym *sym;
unsigned long sympos, addr;
/*
* Check if it's in another .o within the patch module. This also
* checks that the external symbol is unique.
* Since the field widths for objname and symname in the sscanf()
* call are hard-coded and correspond to MODULE_NAME_LEN and
* KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN
* and KSYM_NAME_LEN have the values we expect them to have.
*
* Because the value of MODULE_NAME_LEN can differ among architectures,
* we use the smallest/strictest upper bound possible (56, based on
* the current definition of MODULE_NAME_LEN) to prevent overflows.
*/
return klp_find_object_symbol(pmod->name, name, 0, addr);
BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
relas = (Elf_Rela *) relasec->sh_addr;
/* For each rela in this klp relocation section */
for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
sym = pmod->core_kallsyms.symtab + ELF_R_SYM(relas[i].r_info);
if (sym->st_shndx != SHN_LIVEPATCH) {
pr_err("symbol %s is not marked as a livepatch symbol",
strtab + sym->st_name);
return -EINVAL;
}
/* Format: .klp.sym.objname.symname,sympos */
cnt = sscanf(strtab + sym->st_name,
".klp.sym.%55[^.].%127[^,],%lu",
objname, symname, &sympos);
if (cnt != 3) {
pr_err("symbol %s has an incorrectly formatted name",
strtab + sym->st_name);
return -EINVAL;
}
/* klp_find_object_symbol() treats a NULL objname as vmlinux */
vmlinux = !strcmp(objname, "vmlinux");
ret = klp_find_object_symbol(vmlinux ? NULL : objname,
symname, sympos, &addr);
if (ret)
return ret;
sym->st_value = addr;
}
return 0;
}
static int klp_write_object_relocations(struct module *pmod,
struct klp_object *obj)
{
int ret = 0;
unsigned long val;
struct klp_reloc *reloc;
int i, cnt, ret = 0;
const char *objname, *secname;
char sec_objname[MODULE_NAME_LEN];
Elf_Shdr *sec;
if (WARN_ON(!klp_is_object_loaded(obj)))
return -EINVAL;
if (WARN_ON(!obj->relocs))
return -EINVAL;
objname = klp_is_module(obj) ? obj->name : "vmlinux";
module_disable_ro(pmod);
/* For each klp relocation section */
for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) {
sec = pmod->klp_info->sechdrs + i;
secname = pmod->klp_info->secstrings + sec->sh_name;
if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))
continue;
for (reloc = obj->relocs; reloc->name; reloc++) {
/* discover the address of the referenced symbol */
if (reloc->external) {
if (reloc->sympos > 0) {
pr_err("non-zero sympos for external reloc symbol '%s' is not supported\n",
reloc->name);
ret = -EINVAL;
goto out;
}
ret = klp_find_external_symbol(pmod, reloc->name, &val);
} else
ret = klp_find_object_symbol(obj->name,
reloc->name,
reloc->sympos,
&val);
/*
* Format: .klp.rela.sec_objname.section_name
* See comment in klp_resolve_symbols() for an explanation
* of the selected field width value.
*/
cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname);
if (cnt != 1) {
pr_err("section %s has an incorrectly formatted name",
secname);
ret = -EINVAL;
break;
}
if (strcmp(objname, sec_objname))
continue;
ret = klp_resolve_symbols(sec, pmod);
if (ret)
goto out;
break;
ret = klp_write_module_reloc(pmod, reloc->type, reloc->loc,
val + reloc->addend);
if (ret) {
pr_err("relocation failed for symbol '%s' at 0x%016lx (%d)\n",
reloc->name, val, ret);
goto out;
}
ret = apply_relocate_add(pmod->klp_info->sechdrs,
pmod->core_kallsyms.strtab,
pmod->klp_info->symndx, i, pmod);
if (ret)
break;
}
out:
module_enable_ro(pmod);
return ret;
}
......@@ -298,6 +334,19 @@ static void notrace klp_ftrace_handler(unsigned long ip,
rcu_read_unlock();
}
/*
* Convert a function address into the appropriate ftrace location.
*
* Usually this is just the address of the function, but on some architectures
* it's more complicated so allow them to provide a custom behaviour.
*/
#ifndef klp_get_ftrace_location
static unsigned long klp_get_ftrace_location(unsigned long faddr)
{
return faddr;
}
#endif
static void klp_disable_func(struct klp_func *func)
{
struct klp_ops *ops;
......@@ -312,8 +361,14 @@ static void klp_disable_func(struct klp_func *func)
return;
if (list_is_singular(&ops->func_stack)) {
unsigned long ftrace_loc;
ftrace_loc = klp_get_ftrace_location(func->old_addr);
if (WARN_ON(!ftrace_loc))
return;
WARN_ON(unregister_ftrace_function(&ops->fops));
WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0));
list_del_rcu(&func->stack_node);
list_del(&ops->node);
......@@ -338,6 +393,15 @@ static int klp_enable_func(struct klp_func *func)
ops = klp_find_ops(func->old_addr);
if (!ops) {
unsigned long ftrace_loc;
ftrace_loc = klp_get_ftrace_location(func->old_addr);
if (!ftrace_loc) {
pr_err("failed to find location for function '%s'\n",
func->old_name);
return -EINVAL;
}
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;
......@@ -352,7 +416,7 @@ static int klp_enable_func(struct klp_func *func)
INIT_LIST_HEAD(&ops->func_stack);
list_add_rcu(&func->stack_node, &ops->func_stack);
ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
ret = ftrace_set_filter_ip(&ops->fops, ftrace_loc, 0, 0);
if (ret) {
pr_err("failed to set ftrace filter for function '%s' (%d)\n",
func->old_name, ret);
......@@ -363,7 +427,7 @@ static int klp_enable_func(struct klp_func *func)
if (ret) {
pr_err("failed to register ftrace handler for function '%s' (%d)\n",
func->old_name, ret);
ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0);
goto err;
}
......@@ -706,11 +770,9 @@ static int klp_init_object_loaded(struct klp_patch *patch,
struct klp_func *func;
int ret;
if (obj->relocs) {
ret = klp_write_object_relocations(patch->mod, obj);
if (ret)
return ret;
}
ret = klp_write_object_relocations(patch->mod, obj);
if (ret)
return ret;
klp_for_each_func(obj, func) {
ret = klp_find_object_symbol(obj->name, func->old_name,
......@@ -845,12 +907,18 @@ int klp_register_patch(struct klp_patch *patch)
{
int ret;
if (!klp_initialized())
return -ENODEV;
if (!patch || !patch->mod)
return -EINVAL;
if (!is_livepatch_module(patch->mod)) {
pr_err("module %s is not marked as a livepatch module",
patch->mod->name);
return -EINVAL;
}
if (!klp_initialized())
return -ENODEV;
/*
* A reference is taken on the patch module to prevent it from being
* unloaded. Right now, we don't allow patch modules to unload since
......
kernel/module.c
View file @ be69f70e
......@@ -1973,6 +1973,83 @@ static void module_enable_nx(const struct module *mod) { }
static void module_disable_nx(const struct module *mod) { }
#endif
#ifdef CONFIG_LIVEPATCH
/*
* Persist Elf information about a module. Copy the Elf header,
* section header table, section string table, and symtab section
* index from info to mod->klp_info.
*/
static int copy_module_elf(struct module *mod, struct load_info *info)
{
unsigned int size, symndx;
int ret;
size = sizeof(*mod->klp_info);
mod->klp_info = kmalloc(size, GFP_KERNEL);
if (mod->klp_info == NULL)
return -ENOMEM;
/* Elf header */
size = sizeof(mod->klp_info->hdr);
memcpy(&mod->klp_info->hdr, info->hdr, size);
/* Elf section header table */
size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
mod->klp_info->sechdrs = kmalloc(size, GFP_KERNEL);
if (mod->klp_info->sechdrs == NULL) {
ret = -ENOMEM;
goto free_info;
}
memcpy(mod->klp_info->sechdrs, info->sechdrs, size);
/* Elf section name string table */
size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL);
if (mod->klp_info->secstrings == NULL) {
ret = -ENOMEM;
goto free_sechdrs;
}
memcpy(mod->klp_info->secstrings, info->secstrings, size);
/* Elf symbol section index */
symndx = info->index.sym;
mod->klp_info->symndx = symndx;
/*
* For livepatch modules, core_kallsyms.symtab is a complete
* copy of the original symbol table. Adjust sh_addr to point
* to core_kallsyms.symtab since the copy of the symtab in module
* init memory is freed at the end of do_init_module().
*/
mod->klp_info->sechdrs[symndx].sh_addr = \
(unsigned long) mod->core_kallsyms.symtab;
return 0;
free_sechdrs:
kfree(mod->klp_info->sechdrs);
free_info:
kfree(mod->klp_info);
return ret;
}
static void free_module_elf(struct module *mod)
{
kfree(mod->klp_info->sechdrs);
kfree(mod->klp_info->secstrings);
kfree(mod->klp_info);
}
#else /* !CONFIG_LIVEPATCH */
static int copy_module_elf(struct module *mod, struct load_info *info)
{
return 0;
}
static void free_module_elf(struct module *mod)
{
}
#endif /* CONFIG_LIVEPATCH */
void __weak module_memfree(void *module_region)
{
vfree(module_region);
......@@ -2011,6 +2088,9 @@ static void free_module(struct module *mod)
/* Free any allocated parameters. */
destroy_params(mod->kp, mod->num_kp);
if (is_livepatch_module(mod))
free_module_elf(mod);
/* Now we can delete it from the lists */
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
......@@ -2126,6 +2206,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
(long)sym[i].st_value);
break;
case SHN_LIVEPATCH:
/* Livepatch symbols are resolved by livepatch */
break;
case SHN_UNDEF:
ksym = resolve_symbol_wait(mod, info, name);
/* Ok if resolved. */
......@@ -2174,6 +2258,10 @@ static int apply_relocations(struct module *mod, const struct load_info *info)
if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
continue;
/* Livepatch relocation sections are applied by livepatch */
if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
continue;
if (info->sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(info->sechdrs, info->strtab,
info->index.sym, i, mod);
......@@ -2469,7 +2557,7 @@ static void layout_symtab(struct module *mod, struct load_info *info)
/* Compute total space required for the core symbols' strtab. */
for (ndst = i = 0; i < nsrc; i++) {
if (i == 0 ||
if (i == 0 || is_livepatch_module(mod) ||
is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
info->index.pcpu)) {
strtab_size += strlen(&info->strtab[src[i].st_name])+1;
......@@ -2528,7 +2616,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs;
src = mod->kallsyms->symtab;
for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) {
if (i == 0 ||
if (i == 0 || is_livepatch_module(mod) ||
is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
info->index.pcpu)) {
dst[ndst] = src[i];
......@@ -2667,6 +2755,26 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
return 0;
}
#ifdef CONFIG_LIVEPATCH
static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
{
mod->klp = get_modinfo(info, "livepatch") ? true : false;
return 0;
}
#else /* !CONFIG_LIVEPATCH */
static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
{
if (get_modinfo(info, "livepatch")) {
pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
mod->name);
return -ENOEXEC;
}
return 0;
}
#endif /* CONFIG_LIVEPATCH */
/* Sets info->hdr and info->len. */
static int copy_module_from_user(const void __user *umod, unsigned long len,
struct load_info *info)
......@@ -2821,6 +2929,10 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
"is unknown, you have been warned.\n", mod->name);
}
err = find_livepatch_modinfo(mod, info);
if (err)
return err;
/* Set up license info based on the info section */
set_license(mod, get_modinfo(info, "license"));
......@@ -3494,6 +3606,12 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err < 0)
goto coming_cleanup;
if (is_livepatch_module(mod)) {
err = copy_module_elf(mod, info);
if (err < 0)
goto sysfs_cleanup;
}
/* Get rid of temporary copy. */
free_copy(info);
......@@ -3502,11 +3620,12 @@ static int load_module(struct load_info *info, const char __user *uargs,
return do_init_module(mod);
sysfs_cleanup:
mod_sysfs_teardown(mod);
coming_cleanup:
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
bug_cleanup:
/* module_bug_cleanup needs module_mutex protection */
mutex_lock(&module_mutex);
......
kernel/trace/ftrace.c
View file @ be69f70e
......@@ -1533,7 +1533,19 @@ static int ftrace_cmp_recs(const void *a, const void *b)
return 0;
}
static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
/**
* ftrace_location_range - return the first address of a traced location
* if it touches the given ip range
* @start: start of range to search.
* @end: end of range to search (inclusive). @end points to the last byte
* to check.
*
* Returns rec->ip if the related ftrace location is a least partly within
* the given address range. That is, the first address of the instruction
* that is either a NOP or call to the function tracer. It checks the ftrace
* internal tables to determine if the address belongs or not.
*/
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
......
samples/livepatch/livepatch-sample.c
View file @ be69f70e
......@@ -89,3 +89,4 @@ static void livepatch_exit(void)
module_init(livepatch_init);
module_exit(livepatch_exit);
MODULE_LICENSE("GPL");
MODULE_INFO(livepatch, "Y");
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