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| author | Mark Rutland <mark.rutland@arm.com> | 2016-05-31 14:33:03 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-06-21 19:07:48 +0300 |
| commit | 541ec870ef31433018d245614254bd9d810a9ac3 (patch) | |
| tree | 77fdcd54e4cccd9e081c2f57e14b60b3304cbb43 | |
| parent | 561454e25dfa27aeac9e9d05f88ce7cb43d02d71 (diff) | |
| download | linux-541ec870ef31433018d245614254bd9d810a9ac3.tar.xz | |
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: Mark 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: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/kernel/entry.S | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/fault.c | 13 |
2 files changed, 9 insertions, 6 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 12e8d2bcb3f9..eefffa81c6df 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -532,7 +532,7 @@ el0_ia: enable_dbg_and_irq ct_user_exit mov x0, x26 - orr x1, x25, #1 << 24 // use reserved ISS bit for instruction aborts + mov x1, x25 mov x2, sp bl do_mem_abort b ret_to_user diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d2c124cbd18c..fc5a34a72c6d 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -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_BADACCESS 0x020000 -#define ESR_LNX_EXEC (1 << 24) - static int __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int mm_flags, unsigned long vm_flags, struct task_struct *tsk) @@ -242,7 +240,7 @@ out: 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 fsc_type = esr & ESR_ELx_FSC_TYPE; @@ -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); } +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, struct pt_regs *regs) { @@ -272,14 +275,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, if (user_mode(regs)) mm_flags |= FAULT_FLAG_USER; - if (esr & ESR_LNX_EXEC) { + if (is_el0_instruction_abort(esr)) { vm_flags = VM_EXEC; } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { vm_flags = VM_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) die("Accessing user space memory with fs=KERNEL_DS", regs, esr); |