Commit 541ec870 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas

arm64: kill ESR_LNX_EXEC

Currently we treat ESR_EL1 bit 24 as software-defined for distinguishing
instruction aborts from data aborts, but this bit is architecturally
RES0 for instruction aborts, and could be allocated for an arbitrary
purpose in future. Additionally, we hard-code the value in entry.S
without the mnemonic, making the code difficult to understand.

Instead, remove ESR_LNX_EXEC, and distinguish aborts based on the esr,
which we already pass to the sole use of ESR_LNX_EXEC. A new helper,
is_el0_instruction_abort() is added to make the logic clear. Any
instruction aborts taken from EL1 will already have been handled by
bad_mode, so we need not handle that case in the helper.

For consistency, the existing permission_fault helper is renamed to
is_permission_fault, and the return type is changed to bool. There
should be no functional changes as the return value was a boolean
expression, and the result is only used in another boolean expression.
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Dave P Martin <dave.martin@arm.com>
Cc: Huang Shijie <shijie.huang@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 561454e2
...@@ -532,7 +532,7 @@ el0_ia: ...@@ -532,7 +532,7 @@ el0_ia:
enable_dbg_and_irq enable_dbg_and_irq
ct_user_exit ct_user_exit
mov x0, x26 mov x0, x26
orr x1, x25, #1 << 24 // use reserved ISS bit for instruction aborts mov x1, x25
mov x2, sp mov x2, sp
bl do_mem_abort bl do_mem_abort
b ret_to_user b ret_to_user
......
...@@ -202,8 +202,6 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re ...@@ -202,8 +202,6 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
#define VM_FAULT_BADMAP 0x010000 #define VM_FAULT_BADMAP 0x010000
#define VM_FAULT_BADACCESS 0x020000 #define VM_FAULT_BADACCESS 0x020000
#define ESR_LNX_EXEC (1 << 24)
static int __do_page_fault(struct mm_struct *mm, unsigned long addr, static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
unsigned int mm_flags, unsigned long vm_flags, unsigned int mm_flags, unsigned long vm_flags,
struct task_struct *tsk) struct task_struct *tsk)
...@@ -242,7 +240,7 @@ static int __do_page_fault(struct mm_struct *mm, unsigned long addr, ...@@ -242,7 +240,7 @@ static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
return fault; return fault;
} }
static inline int permission_fault(unsigned int esr) static inline bool is_permission_fault(unsigned int esr)
{ {
unsigned int ec = ESR_ELx_EC(esr); unsigned int ec = ESR_ELx_EC(esr);
unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
...@@ -250,6 +248,11 @@ static inline int permission_fault(unsigned int esr) ...@@ -250,6 +248,11 @@ static inline int permission_fault(unsigned int esr)
return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM); return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);
} }
static bool is_el0_instruction_abort(unsigned int esr)
{
return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}
static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs) struct pt_regs *regs)
{ {
...@@ -272,14 +275,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, ...@@ -272,14 +275,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
if (user_mode(regs)) if (user_mode(regs))
mm_flags |= FAULT_FLAG_USER; mm_flags |= FAULT_FLAG_USER;
if (esr & ESR_LNX_EXEC) { if (is_el0_instruction_abort(esr)) {
vm_flags = VM_EXEC; vm_flags = VM_EXEC;
} else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
vm_flags = VM_WRITE; vm_flags = VM_WRITE;
mm_flags |= FAULT_FLAG_WRITE; mm_flags |= FAULT_FLAG_WRITE;
} }
if (permission_fault(esr) && (addr < USER_DS)) { if (is_permission_fault(esr) && (addr < USER_DS)) {
if (get_fs() == KERNEL_DS) if (get_fs() == KERNEL_DS)
die("Accessing user space memory with fs=KERNEL_DS", regs, esr); die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
......
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