[PATCH v2 3/5] arm64: consistently pass ESR_ELx to die()
Anshuman Khandual
anshuman.khandual at arm.com
Tue Sep 13 22:52:40 PDT 2022
On 9/13/22 15:47, Mark Rutland wrote:
> Currently, bug_handler() and kasan_handler() call die() with '0' as the
> 'err' value, whereas die_kernel_fault() passes the ESR_ELx value.
>
> For consistency, this patch ensures we always pass the ESR_ELx value to
> die(). As this is only called for exceptions taken from kernel mode,
> there should be no user-visible change as a result of this patch.
>
> For UNDEFINED exceptions, I've had to modify do_undefinstr() and its
> callers to pass the ESR_ELx value. In all cases the ESR_ELx value had
> already been read and was available.
>
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Alexandru Elisei <alexandru.elisei at arm.com>
> Cc: Amit Daniel Kachhap <amit.kachhap at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: James Morse <james.morse at arm.com>
> Cc: Will Deacon <will at kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>
> ---
> arch/arm64/include/asm/exception.h | 2 +-
> arch/arm64/kernel/entry-common.c | 14 +++++++-------
> arch/arm64/kernel/traps.c | 14 +++++++-------
> 3 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
> index d94aecff96902..28c0275666e12 100644
> --- a/arch/arm64/include/asm/exception.h
> +++ b/arch/arm64/include/asm/exception.h
> @@ -58,7 +58,7 @@ asmlinkage void call_on_irq_stack(struct pt_regs *regs,
> asmlinkage void asm_exit_to_user_mode(struct pt_regs *regs);
>
> void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs);
> -void do_undefinstr(struct pt_regs *regs);
> +void do_undefinstr(struct pt_regs *regs, unsigned long esr);
> void do_bti(struct pt_regs *regs);
> void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr,
> struct pt_regs *regs);
> diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
> index c75ca36b4a491..3dd17ef6d6d8b 100644
> --- a/arch/arm64/kernel/entry-common.c
> +++ b/arch/arm64/kernel/entry-common.c
> @@ -379,11 +379,11 @@ static void noinstr el1_pc(struct pt_regs *regs, unsigned long esr)
> exit_to_kernel_mode(regs);
> }
>
> -static void noinstr el1_undef(struct pt_regs *regs)
> +static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr)
> {
> enter_from_kernel_mode(regs);
> local_daif_inherit(regs);
> - do_undefinstr(regs);
> + do_undefinstr(regs, esr);
> local_daif_mask();
> exit_to_kernel_mode(regs);
> }
> @@ -425,7 +425,7 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs)
> break;
> case ESR_ELx_EC_SYS64:
> case ESR_ELx_EC_UNKNOWN:
> - el1_undef(regs);
> + el1_undef(regs, esr);
> break;
> case ESR_ELx_EC_BREAKPT_CUR:
> case ESR_ELx_EC_SOFTSTP_CUR:
> @@ -582,11 +582,11 @@ static void noinstr el0_sp(struct pt_regs *regs, unsigned long esr)
> exit_to_user_mode(regs);
> }
>
> -static void noinstr el0_undef(struct pt_regs *regs)
> +static void noinstr el0_undef(struct pt_regs *regs, unsigned long esr)
> {
> enter_from_user_mode(regs);
> local_daif_restore(DAIF_PROCCTX);
> - do_undefinstr(regs);
> + do_undefinstr(regs, esr);
> exit_to_user_mode(regs);
> }
>
> @@ -670,7 +670,7 @@ asmlinkage void noinstr el0t_64_sync_handler(struct pt_regs *regs)
> el0_pc(regs, esr);
> break;
> case ESR_ELx_EC_UNKNOWN:
> - el0_undef(regs);
> + el0_undef(regs, esr);
> break;
> case ESR_ELx_EC_BTI:
> el0_bti(regs);
> @@ -788,7 +788,7 @@ asmlinkage void noinstr el0t_32_sync_handler(struct pt_regs *regs)
> case ESR_ELx_EC_CP14_MR:
> case ESR_ELx_EC_CP14_LS:
> case ESR_ELx_EC_CP14_64:
> - el0_undef(regs);
> + el0_undef(regs, esr);
> break;
> case ESR_ELx_EC_CP15_32:
> case ESR_ELx_EC_CP15_64:
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index da8ffef6f7c58..05999cde870a9 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -485,7 +485,7 @@ void arm64_notify_segfault(unsigned long addr)
> force_signal_inject(SIGSEGV, code, addr, 0);
> }
>
> -void do_undefinstr(struct pt_regs *regs)
> +void do_undefinstr(struct pt_regs *regs, unsigned long esr)
> {
> /* check for AArch32 breakpoint instructions */
> if (!aarch32_break_handler(regs))
> @@ -495,7 +495,7 @@ void do_undefinstr(struct pt_regs *regs)
> return;
>
> if (!user_mode(regs))
> - die("Oops - Undefined instruction", regs, 0);
> + die("Oops - Undefined instruction", regs, esr);
>
> force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
> }
> @@ -760,7 +760,7 @@ void do_cp15instr(unsigned long esr, struct pt_regs *regs)
> hook_base = cp15_64_hooks;
> break;
> default:
> - do_undefinstr(regs);
> + do_undefinstr(regs, esr);
> return;
> }
>
> @@ -775,7 +775,7 @@ void do_cp15instr(unsigned long esr, struct pt_regs *regs)
> * EL0. Fall back to our usual undefined instruction handler
> * so that we handle these consistently.
> */
> - do_undefinstr(regs);
> + do_undefinstr(regs, esr);
> }
> NOKPROBE_SYMBOL(do_cp15instr);
> #endif
> @@ -795,7 +795,7 @@ void do_sysinstr(unsigned long esr, struct pt_regs *regs)
> * back to our usual undefined instruction handler so that we handle
> * these consistently.
> */
> - do_undefinstr(regs);
> + do_undefinstr(regs, esr);
> }
> NOKPROBE_SYMBOL(do_sysinstr);
>
> @@ -972,7 +972,7 @@ static int bug_handler(struct pt_regs *regs, unsigned long esr)
> {
> switch (report_bug(regs->pc, regs)) {
> case BUG_TRAP_TYPE_BUG:
> - die("Oops - BUG", regs, 0);
> + die("Oops - BUG", regs, esr);
> break;
>
> case BUG_TRAP_TYPE_WARN:
> @@ -1040,7 +1040,7 @@ static int kasan_handler(struct pt_regs *regs, unsigned long esr)
> * This is something that might be fixed at some point in the future.
> */
> if (!recover)
> - die("Oops - KASAN", regs, 0);
> + die("Oops - KASAN", regs, esr);
>
> /* If thread survives, skip over the brk instruction and continue: */
> arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
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