- 16 Jun, 2021 40 commits
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Daniel Axtens authored
Make our stack-walking code KASAN-safe by using __no_sanitize_address. Generic code, arm64, s390 and x86 all make accesses unchecked for similar sorts of reasons: when unwinding a stack, we might touch memory that KASAN has marked as being out-of-bounds. In ppc64 KASAN development, I hit this sometimes when checking for an exception frame - because we're checking an arbitrary offset into the stack frame. See commit 20955746 ("s390/kasan: avoid false positives during stack unwind"), commit bcaf669b ("arm64: disable kasan when accessing frame->fp in unwind_frame"), commit 91e08ab0 ("x86/dumpstack: Prevent KASAN false positive warnings") and commit 6e22c836 ("tracing, kasan: Silence Kasan warning in check_stack of stack_tracer"). Signed-off-by:
Daniel Axtens <dja@axtens.net> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210614120907.1952321-1-dja@axtens.net
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Athira Rajeev authored
With the MMCR0 control bit (PMCCEXT) in ISA v3.1, read access to group B registers is restricted when MMCR0 PMCC=0b00. In other platforms (like power9), the older behaviour works where group B PMU SPRs are readable. Patch creates a selftest which verifies that the test takes a SIGILL when attempting to read PMU registers via helper function "dump_ebb_state" for ISA v3.1. Signed-off-by:
Athira Rajeev <atrajeev@linux.vnet.ibm.com> Tested-by:
Nageswara R Sastry <rnsastry@linux.ibm.com <mailto:rnsastry@linux.ibm.com>> Signed-off-by:
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Athira Rajeev authored
The "no_handler_test" in ebb selftests attempts to read the PMU registers twice via helper function "dump_ebb_state". First dump is just before closing of event and the second invocation is done after closing of the event. The original intention of second dump_ebb_state was to dump the state of registers at the end of the test when the counters are frozen. But this will be achieved with the first call itself since sample period is set to low value and PMU will be frozen by then. Hence patch removes the dump which was done before closing of the event. Reported-by:
Shirisha Ganta <shirisha.ganta1@ibm.com> Signed-off-by:
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Christophe Leroy authored
update_power8_hid0() is used only by powernv platform subcore.c Move it there. Signed-off-by:
Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by:
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Christophe Leroy authored
proc_trap() has never been used, remove it. Signed-off-by:
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Christophe Leroy authored
Comment says that __main() is there to make GCC happy. It's been there since the implementation of ppc arch in Linux 1.3.45. ppc32 is the only architecture having that. Even ppc64 doesn't have it. Seems like GCC is still happy without it. Drop it for good. Signed-off-by:
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Christophe Leroy authored
PTE_SIZE means PTE page table size in most placed, whereas in hash_low.S in means size of one entry in the table. Rename it PTE_T_SIZE, and define it directly in hash_low.S instead of going through asm-offsets. Signed-off-by:
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Christophe Leroy authored
Don't duplicate swapper_pg_dir[] in each platform's head.S Define it in mm/pgtable.c Define MAX_PTRS_PER_PGD because on book3s/64 PTRS_PER_PGD is not a constant. Signed-off-by:
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Christophe Leroy authored
At the time being, empty_zero_page[] is defined in each platform head.S. Define it in mm/mem.c instead, and put it in BSS section instead of the DATA section. Commit 5227cfa7 ("arm64: mm: place empty_zero_page in bss") explains why it is interesting to have it in BSS. Signed-off-by:
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Christophe Leroy authored
gettid() is 10% lighter than getppid(), use it for null_syscall selftest. Signed-off-by:
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Christophe Leroy authored
DEBUG_HARDER is not user selectable. Remove it together with related messages. Also remove two pr_devel() messages that should likely have been pr_hard(). Signed-off-by:
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Christophe Leroy authored
DEBUG_CLAMP_LAST_CONTEXT was there in the old days to reduce number of contexts in order to ease debugging implementation of context switching, but that's been quite stable during years now. As it is not user selectable, remove it. Signed-off-by:
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Christophe Leroy authored
mmu_context handling has been there for years, so we would know if there was problems with maps. DEBUG_MAP_CONSISTENCY is not user selectable, remove it. Signed-off-by:
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Christophe Leroy authored
Everything can be done even when CONFIG_SMP is not selected. Just use IS_ENABLED() where relevant and rely on GCC to opt out unneeded code and variables when CONFIG_SMP is not set. Signed-off-by:
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Christophe Leroy authored
ppc8xx already has set_context() in C. Other ones have it in assembly. The only thing it does is to write the context id into SPRN_PID. Do it in C. Signed-off-by:
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Christophe Leroy authored
Instead of duplicating the update of BDI2000 pointers in set_context(), do it directly from switch_mmu_context(). Signed-off-by:
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Christophe Leroy authored
All KUAP helpers defined in asm/kup.h are single line functions that should be inlined. But on book3s/32 build, we get many instances of <prevent_write_to_user.constprop.0>. Force inlining of those helpers. Signed-off-by:
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Christophe Leroy authored
prevent_user_access() doesn't use anymore to/from/size parameters. Remove them. Signed-off-by:
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Christophe Leroy authored
book3s/32 was the only user of KUAP_CURRENT_XXX. After rework of book3s/32 KUAP, it is not used anymore. Remove them. Signed-off-by:
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Christophe Leroy authored
Now that KUAP and KUEP have been significantly optimised and can be disabled at boot time using 'nosmap' and 'nosmep' kernel parameters, them can be active by default like in other powerpc platforms. It is still possible to disable them completely in the configuration. Signed-off-by:
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Christophe Leroy authored
On book3s/32, KUAP is provided by toggling Ks bit in segment registers. One segment register addresses 256M of virtual memory. At the time being, KUAP implements a complex logic to apply the unlock/lock on the exact number of segments covering the user range to access, with saving the boundaries of the range of segments in a member of thread struct. But most if not all user accesses are within a single segment. Rework KUAP with a different approach: - Open only one segment, the one corresponding to the starting address of the range to be accessed. - If a second segment is involved, it will generate a page fault. The segment will then be open by the page fault handler. The kuap member of thread struct will now contain: - The start address of the current on going user access, that will be used to know which segment to lock at the end of the user access. - ~0 when no user access is open - ~1 when additionnal segments are opened by a page fault. Then, at lock time - When only one segment is open, close it. - When several segments are open, close all user segments. Almost 100% of the time, only one segment will be involved. In interrupts, inline the function that unlock/lock all segments, because not inlining them implies a lot of register save/restore. With the patch, writing value 128 in userspace in perf_copy_attr() is done with 16 instructions: 3890: 93 82 04 dc stw r28,1244(r2) 3894: 7d 20 e5 26 mfsrin r9,r28 3898: 55 29 00 80 rlwinm r9,r9,0,2,0 389c: 7d 20 e1 e4 mtsrin r9,r28 38a0: 4c 00 01 2c isync 38a4: 39 20 00 80 li r9,128 38a8: 91 3c 00 00 stw r9,0(r28) 38ac: 81 42 04 dc lwz r10,1244(r2) 38b0: 39 00 ff ff li r8,-1 38b4: 91 02 04 dc stw r8,1244(r2) 38b8: 2c 0a ff fe cmpwi r10,-2 38bc: 41 82 00 88 beq 3944 <perf_copy_attr+0x36c> 38c0: 7d 20 55 26 mfsrin r9,r10 38c4: 65 29 40 00 oris r9,r9,16384 38c8: 7d 20 51 e4 mtsrin r9,r10 38cc: 4c 00 01 2c isync ... 3944: 48 00 00 01 bl 3944 <perf_copy_attr+0x36c> 3944: R_PPC_REL24 kuap_lock_all_ool Before the patch it was 118 instructions. In reality only 42 are executed in most cases, but GCC is not able to see that a properly aligned user access cannot involve more than one segment. 5060: 39 1d 00 04 addi r8,r29,4 5064: 3d 20 b0 00 lis r9,-20480 5068: 7c 08 48 40 cmplw r8,r9 506c: 40 81 00 08 ble 5074 <perf_copy_attr+0x2cc> 5070: 3d 00 b0 00 lis r8,-20480 5074: 39 28 ff ff addi r9,r8,-1 5078: 57 aa 00 06 rlwinm r10,r29,0,0,3 507c: 55 29 27 3e rlwinm r9,r9,4,28,31 5080: 39 29 00 01 addi r9,r9,1 5084: 7d 29 53 78 or r9,r9,r10 5088: 91 22 04 dc stw r9,1244(r2) 508c: 7d 20 ed 26 mfsrin r9,r29 5090: 55 29 00 80 rlwinm r9,r9,0,2,0 5094: 7c 08 50 40 cmplw r8,r10 5098: 40 81 00 c0 ble 5158 <perf_copy_attr+0x3b0> 509c: 7d 46 50 f8 not r6,r10 50a0: 7c c6 42 14 add r6,r6,r8 50a4: 54 c6 27 be rlwinm r6,r6,4,30,31 50a8: 7d 20 51 e4 mtsrin r9,r10 50ac: 3c ea 10 00 addis r7,r10,4096 50b0: 39 29 01 11 addi r9,r9,273 50b4: 7f 88 38 40 cmplw cr7,r8,r7 50b8: 55 29 02 06 rlwinm r9,r9,0,8,3 50bc: 40 9d 00 9c ble cr7,5158 <perf_copy_attr+0x3b0> 50c0: 2f 86 00 00 cmpwi cr7,r6,0 50c4: 41 9e 00 4c beq cr7,5110 <perf_copy_attr+0x368> 50c8: 2f 86 00 01 cmpwi cr7,r6,1 50cc: 41 9e 00 2c beq cr7,50f8 <perf_copy_attr+0x350> 50d0: 2f 86 00 02 cmpwi cr7,r6,2 50d4: 41 9e 00 14 beq cr7,50e8 <perf_copy_attr+0x340> 50d8: 7d 20 39 e4 mtsrin r9,r7 50dc: 39 29 01 11 addi r9,r9,273 50e0: 3c e7 10 00 addis r7,r7,4096 50e4: 55 29 02 06 rlwinm r9,r9,0,8,3 50e8: 7d 20 39 e4 mtsrin r9,r7 50ec: 39 29 01 11 addi r9,r9,273 50f0: 3c e7 10 00 addis r7,r7,4096 50f4: 55 29 02 06 rlwinm r9,r9,0,8,3 50f8: 7d 20 39 e4 mtsrin r9,r7 50fc: 3c e7 10 00 addis r7,r7,4096 5100: 39 29 01 11 addi r9,r9,273 5104: 7f 88 38 40 cmplw cr7,r8,r7 5108: 55 29 02 06 rlwinm r9,r9,0,8,3 510c: 40 9d 00 4c ble cr7,5158 <perf_copy_attr+0x3b0> 5110: 7d 20 39 e4 mtsrin r9,r7 5114: 39 29 01 11 addi r9,r9,273 5118: 3c c7 10 00 addis r6,r7,4096 511c: 55 29 02 06 rlwinm r9,r9,0,8,3 5120: 7d 20 31 e4 mtsrin r9,r6 5124: 39 29 01 11 addi r9,r9,273 5128: 3c c6 10 00 addis r6,r6,4096 512c: 55 29 02 06 rlwinm r9,r9,0,8,3 5130: 7d 20 31 e4 mtsrin r9,r6 5134: 39 29 01 11 addi r9,r9,273 5138: 3c c7 30 00 addis r6,r7,12288 513c: 55 29 02 06 rlwinm r9,r9,0,8,3 5140: 7d 20 31 e4 mtsrin r9,r6 5144: 3c e7 40 00 addis r7,r7,16384 5148: 39 29 01 11 addi r9,r9,273 514c: 7f 88 38 40 cmplw cr7,r8,r7 5150: 55 29 02 06 rlwinm r9,r9,0,8,3 5154: 41 9d ff bc bgt cr7,5110 <perf_copy_attr+0x368> 5158: 4c 00 01 2c isync 515c: 39 20 00 80 li r9,128 5160: 91 3d 00 00 stw r9,0(r29) 5164: 38 e0 00 00 li r7,0 5168: 90 e2 04 dc stw r7,1244(r2) 516c: 7d 20 ed 26 mfsrin r9,r29 5170: 65 29 40 00 oris r9,r9,16384 5174: 40 81 00 c0 ble 5234 <perf_copy_attr+0x48c> 5178: 7d 47 50 f8 not r7,r10 517c: 7c e7 42 14 add r7,r7,r8 5180: 54 e7 27 be rlwinm r7,r7,4,30,31 5184: 7d 20 51 e4 mtsrin r9,r10 5188: 3d 4a 10 00 addis r10,r10,4096 518c: 39 29 01 11 addi r9,r9,273 5190: 7c 08 50 40 cmplw r8,r10 5194: 55 29 02 06 rlwinm r9,r9,0,8,3 5198: 40 81 00 9c ble 5234 <perf_copy_attr+0x48c> 519c: 2c 07 00 00 cmpwi r7,0 51a0: 41 82 00 4c beq 51ec <perf_copy_attr+0x444> 51a4: 2c 07 00 01 cmpwi r7,1 51a8: 41 82 00 2c beq 51d4 <perf_copy_attr+0x42c> 51ac: 2c 07 00 02 cmpwi r7,2 51b0: 41 82 00 14 beq 51c4 <perf_copy_attr+0x41c> 51b4: 7d 20 51 e4 mtsrin r9,r10 51b8: 39 29 01 11 addi r9,r9,273 51bc: 3d 4a 10 00 addis r10,r10,4096 51c0: 55 29 02 06 rlwinm r9,r9,0,8,3 51c4: 7d 20 51 e4 mtsrin r9,r10 51c8: 39 29 01 11 addi r9,r9,273 51cc: 3d 4a 10 00 addis r10,r10,4096 51d0: 55 29 02 06 rlwinm r9,r9,0,8,3 51d4: 7d 20 51 e4 mtsrin r9,r10 51d8: 3d 4a 10 00 addis r10,r10,4096 51dc: 39 29 01 11 addi r9,r9,273 51e0: 7c 08 50 40 cmplw r8,r10 51e4: 55 29 02 06 rlwinm r9,r9,0,8,3 51e8: 40 81 00 4c ble 5234 <perf_copy_attr+0x48c> 51ec: 7d 20 51 e4 mtsrin r9,r10 51f0: 39 29 01 11 addi r9,r9,273 51f4: 3c ea 10 00 addis r7,r10,4096 51f8: 55 29 02 06 rlwinm r9,r9,0,8,3 51fc: 7d 20 39 e4 mtsrin r9,r7 5200: 39 29 01 11 addi r9,r9,273 5204: 3c e7 10 00 addis r7,r7,4096 5208: 55 29 02 06 rlwinm r9,r9,0,8,3 520c: 7d 20 39 e4 mtsrin r9,r7 5210: 39 29 01 11 addi r9,r9,273 5214: 3c ea 30 00 addis r7,r10,12288 5218: 55 29 02 06 rlwinm r9,r9,0,8,3 521c: 7d 20 39 e4 mtsrin r9,r7 5220: 3d 4a 40 00 addis r10,r10,16384 5224: 39 29 01 11 addi r9,r9,273 5228: 7c 08 50 40 cmplw r8,r10 522c: 55 29 02 06 rlwinm r9,r9,0,8,3 5230: 41 81 ff bc bgt 51ec <perf_copy_attr+0x444> 5234: 4c 00 01 2c isync Signed-off-by: -
Christophe Leroy authored
PPC64 uses MMU features to enable/disable KUAP at boot time. But feature fixups are applied way too early on PPC32. Now that all KUAP related actions are in C following the conversion of KUAP initial setup and context switch in C, static branches can be used to enable/disable KUAP. Signed-off-by:
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Christophe Leroy authored
PPC64 uses MMU features to enable/disable KUEP at boot time. But feature fixups are applied way too early on PPC32. Now that all KUEP related actions are in C following the conversion of KUEP initial setup and context switch in C, static branches can be used to enable/disable KUEP. Signed-off-by:
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Christophe Leroy authored
In order to selectively activate KUAP and KUEP in a following patch, perform KUAP and KUEP initialisation in C. Unlike PPC64, PPC32 doesn't have an early_setup_secondary(), so do it in start_secondary(). Signed-off-by:
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Christophe Leroy authored
segment register has VSID on bits 8-31. Bits 4-7 are reserved, there is no requirement to set them to 0. VSIDs are calculated from VSID of SR0 by adding 0x111. Even with highest possible VSID which would be 0xFFFFF0, adding 16 times 0x111 results in 0x1001100. So, the reserved bits are never overflowed, no need to clear the reserved bits after each calculation. Signed-off-by:
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Christophe Leroy authored
switch_mmu_context() does things that can easily be done in C. For updating user segments, we have update_user_segments(). As mentionned in commit b5efec00 ("powerpc/32s: Move KUEP locking/unlocking in C"), update_user_segments() has the loop unrolled which is a significant performance gain. Signed-off-by:
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Christophe Leroy authored
In order to reuse it in switch_mmu_context(), this patch moves CTX_TO_VSID() macro into asm/book3s/32/mmu-hash.h Signed-off-by:
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Christophe Leroy authored
KUEP implements the update of user segment registers. Move it into mmu-hash.h in order to use it from other places. And inline kuep_lock() and kuep_unlock(). Inlining kuep_lock() is important for system_call_exception(), otherwise system_call_exception() has to save into stack the system call parameters that are used just after, and doing that takes more instructions than kuep_lock() itself. Signed-off-by:
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Christophe Leroy authored
Avoids the #ifdef in mmu.c Signed-off-by:
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Christophe Leroy authored
PPC64 uses MMU features to enable/disable KUAP at boot time. But feature fixups are applied way too early on PPC32. But since commit c1672883 ("powerpc/32: Manage KUAP in C"), all KUAP is in C so it is now possible to use static branches. Signed-off-by:
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Christophe Leroy authored
Powerpc 44x has two bits for exec protection in TLBs: one for user (UX) and one for superviser (SX). Clear SX on user pages in TLB miss handlers to provide KUEP. Signed-off-by:
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Christophe Leroy authored
Since commit Fixes: 555904d0 ("powerpc/8xx: MM_SLICE is not needed anymore"), CONFIG_PPC_MMU_NOHASH_32 has not been used. Remove it. Reported-by:
Tom Rix <trix@redhat.com> Signed-off-by:
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Christophe Leroy authored
Use PPC_RAW_ macros to simplify the code. And use PPC_LO/PPC_HI instead of IMM_L/IMM_H which are for internal use inside ppc-opcode.h Those macros are self explanatory, comments can go as well. Signed-off-by:
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Christophe Leroy authored
Now that lines can be up to 100 chars long, minimise the amount of split lines to increase readability. Signed-off-by:
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Christophe Leroy authored
nip is already an unsigned long, no cast needed. op_callback_addr and emulate_step_addr are kprobe_opcode_t *. There value is obtained with ppc_kallsyms_lookup_name() which returns 'unsigned long', and there values are used create_branch() which expects 'unsigned long'. So change them to 'unsigned long' to avoid casting them back and forth. can_optimize() used p->addr several times as 'unsigned long'. Use a local 'unsigned long' variable and avoid casting multiple times. Signed-off-by:
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Christophe Leroy authored
ppc_inst() ppc_inst_prefixed() ppc_inst_swab() can easily be made common to both PPC32 and PPC64. Signed-off-by:
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Christophe Leroy authored
'struct ppc_inst' is an internal representation of an instruction, but in-memory instructions are and will remain a table of 'u32' forever. Replace all 'struct ppc_inst *' used for locating an instruction in memory by 'u32 *'. This removes a lot of undue casts to 'struct ppc_inst *'. It also helps locating ab-use of 'struct ppc_inst' dereference. Signed-off-by:
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Christophe Leroy authored
'struct ppc_inst' is meant to represent an instruction internally, it is not meant to dereference code in memory. For testing code patching, use patch_instruction() to properly write into memory the code to be tested. Signed-off-by:
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Christophe Leroy authored
instr_is_branch_to_addr() is only used in code-patching.c Make it static. Signed-off-by:
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Christophe Leroy authored
'struct ppc_inst' is an internal structure to represent an instruction, it is not directly the representation of that instruction in text code. It is not meant to map and dereference code. Dereferencing code directly through 'struct ppc_inst' has two main issues: - On powerpc, structs are expected to be 8 bytes aligned while code is spread every 4 byte. - Should a non prefixed instruction lie at the end of the page and the following page not be mapped, it would generate a page fault. In-memory code must be accessed with ppc_inst_read(). Signed-off-by:
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