| Message ID | 20191003171642.135652-3-james.morse@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Convert entry.S synchronous exception handling to C | expand |
On Thu, Oct 03, 2019 at 06:16:36PM +0100, James Morse wrote: > Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded > stack frame") arm64 has has not used the __exception annotation to dump > the pt_regs during stack tracing. in_exception_text() has no callers. > > This annotation is only used to blacklist kprobes, it means the same as > __kprobes. > > Section annotations like this require the functions to be grouped > together between the start/end markers, and placed according to > the linker script. For kprobes we also have NOKPROBE_SYMBOL() which > logs the symbol address in a section that kprobes parses and > blacklists at boot. > > Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of > blacklisted symbols, and saves us from having an arm64 specific > spelling of __kprobes. > > Signed-off-by: James Morse <james.morse@arm.com> > Cc: Masami Hiramatsu <mhiramat@kernel.org> > > --- > (__exception_irq_entry means no-kprobes and optionally in a section > ftrace can use to pretty-print interrupt handler boundaries.) > --- > arch/arm64/include/asm/exception.h | 4 ++-- > arch/arm64/include/asm/traps.h | 10 --------- > arch/arm64/kernel/probes/kprobes.c | 4 ---- > arch/arm64/kernel/traps.c | 10 ++++++--- > arch/arm64/kernel/vmlinux.lds.S | 3 --- > arch/arm64/mm/fault.c | 34 +++++++++++++++--------------- > 6 files changed, 26 insertions(+), 39 deletions(-) > > diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h > index a17393ff6677..b0b3ba56e919 100644 > --- a/arch/arm64/include/asm/exception.h > +++ b/arch/arm64/include/asm/exception.h [...] > -asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint, > - unsigned int esr, > - struct pt_regs *regs) > +asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint, > + unsigned int esr, struct pt_regs *regs) > { > const struct fault_info *inf = esr_to_debug_fault_info(esr); > unsigned long pc = instruction_pointer(regs); I assume you meant to add NOKPROBE_SYMBOL(do_debug_exception) here. Assuming so, and with that fixed up: Acked-by: Mark Rutland <mark.rutland@arm.com> Mark.
On 03/10/2019 19:16, James Morse wrote: > Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded > stack frame") arm64 has has not used the __exception annotation to dump s/has has not/has not/ ?
On Fri, 4 Oct 2019 11:17:17 +0100 Mark Rutland <mark.rutland@arm.com> wrote: > On Thu, Oct 03, 2019 at 06:16:36PM +0100, James Morse wrote: > > Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded > > stack frame") arm64 has has not used the __exception annotation to dump > > the pt_regs during stack tracing. in_exception_text() has no callers. > > > > This annotation is only used to blacklist kprobes, it means the same as > > __kprobes. > > > > Section annotations like this require the functions to be grouped > > together between the start/end markers, and placed according to > > the linker script. For kprobes we also have NOKPROBE_SYMBOL() which > > logs the symbol address in a section that kprobes parses and > > blacklists at boot. > > > > Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of > > blacklisted symbols, and saves us from having an arm64 specific > > spelling of __kprobes. > > > > Signed-off-by: James Morse <james.morse@arm.com> > > Cc: Masami Hiramatsu <mhiramat@kernel.org> > > > > --- > > (__exception_irq_entry means no-kprobes and optionally in a section > > ftrace can use to pretty-print interrupt handler boundaries.) > > --- > > arch/arm64/include/asm/exception.h | 4 ++-- > > arch/arm64/include/asm/traps.h | 10 --------- > > arch/arm64/kernel/probes/kprobes.c | 4 ---- > > arch/arm64/kernel/traps.c | 10 ++++++--- > > arch/arm64/kernel/vmlinux.lds.S | 3 --- > > arch/arm64/mm/fault.c | 34 +++++++++++++++--------------- > > 6 files changed, 26 insertions(+), 39 deletions(-) > > > > diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h > > index a17393ff6677..b0b3ba56e919 100644 > > --- a/arch/arm64/include/asm/exception.h > > +++ b/arch/arm64/include/asm/exception.h > > [...] > > > -asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint, > > - unsigned int esr, > > - struct pt_regs *regs) > > +asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint, > > + unsigned int esr, struct pt_regs *regs) > > { > > const struct fault_info *inf = esr_to_debug_fault_info(esr); > > unsigned long pc = instruction_pointer(regs); > > I assume you meant to add NOKPROBE_SYMBOL(do_debug_exception) here. > > Assuming so, and with that fixed up: > > Acked-by: Mark Rutland <mark.rutland@arm.com> Good catch, if so, this looks good to me too. with that fixed up: Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Thanks!
Hi guys, On 04/10/2019 15:10, Masami Hiramatsu wrote: > On Fri, 4 Oct 2019 11:17:17 +0100 > Mark Rutland <mark.rutland@arm.com> wrote: >> On Thu, Oct 03, 2019 at 06:16:36PM +0100, James Morse wrote: >>> Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded >>> stack frame") arm64 has has not used the __exception annotation to dump >>> the pt_regs during stack tracing. in_exception_text() has no callers. >>> >>> This annotation is only used to blacklist kprobes, it means the same as >>> __kprobes. >>> >>> Section annotations like this require the functions to be grouped >>> together between the start/end markers, and placed according to >>> the linker script. For kprobes we also have NOKPROBE_SYMBOL() which >>> logs the symbol address in a section that kprobes parses and >>> blacklists at boot. >>> >>> Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of >>> blacklisted symbols, and saves us from having an arm64 specific >>> spelling of __kprobes. >>> diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h >>> index a17393ff6677..b0b3ba56e919 100644 >>> --- a/arch/arm64/include/asm/exception.h >>> +++ b/arch/arm64/include/asm/exception.h >> >> [...] >> >>> -asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint, >>> - unsigned int esr, >>> - struct pt_regs *regs) >>> +asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint, >>> + unsigned int esr, struct pt_regs *regs) >>> { >>> const struct fault_info *inf = esr_to_debug_fault_info(esr); >>> unsigned long pc = instruction_pointer(regs); >> >> I assume you meant to add NOKPROBE_SYMBOL(do_debug_exception) here. >> >> Assuming so, and with that fixed up: >> >> Acked-by: Mark Rutland <mark.rutland@arm.com> > > Good catch, if so, this looks good to me too. I should have noted it in the commit message, but the NOKPROBE_SYMBOL(do_debug_exception) is already there! Added by commit 2dd0e8d2d2a15 ("arm64: Kprobes with single stepping support"). (kprobing the debug handler is so bad, we blacklist it twice!) I'll fix the commit message. > with that fixed up: > > Acked-by: Masami Hiramatsu <mhiramat@kernel.org> I assume you're both happy for me to apply these tags. Thanks, James
On 04/10/2019 14:03, Marc Gonzalez wrote: > On 03/10/2019 19:16, James Morse wrote: > >> Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded >> stack frame") arm64 has has not used the __exception annotation to dump > > s/has has not/has not/ ? oops! Thanks, James
On Fri, Oct 04, 2019 at 05:08:11PM +0100, James Morse wrote: > On 04/10/2019 15:10, Masami Hiramatsu wrote: > > On Fri, 4 Oct 2019 11:17:17 +0100 > > Mark Rutland <mark.rutland@arm.com> wrote: > >> On Thu, Oct 03, 2019 at 06:16:36PM +0100, James Morse wrote: > >>> Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded > >>> stack frame") arm64 has has not used the __exception annotation to dump > >>> the pt_regs during stack tracing. in_exception_text() has no callers. > >>> > >>> This annotation is only used to blacklist kprobes, it means the same as > >>> __kprobes. > >>> > >>> Section annotations like this require the functions to be grouped > >>> together between the start/end markers, and placed according to > >>> the linker script. For kprobes we also have NOKPROBE_SYMBOL() which > >>> logs the symbol address in a section that kprobes parses and > >>> blacklists at boot. > >>> > >>> Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of > >>> blacklisted symbols, and saves us from having an arm64 specific > >>> spelling of __kprobes. > > >>> diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h > >>> index a17393ff6677..b0b3ba56e919 100644 > >>> --- a/arch/arm64/include/asm/exception.h > >>> +++ b/arch/arm64/include/asm/exception.h > >> > >> [...] > >> > >>> -asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint, > >>> - unsigned int esr, > >>> - struct pt_regs *regs) > >>> +asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint, > >>> + unsigned int esr, struct pt_regs *regs) > >>> { > >>> const struct fault_info *inf = esr_to_debug_fault_info(esr); > >>> unsigned long pc = instruction_pointer(regs); > >> > >> I assume you meant to add NOKPROBE_SYMBOL(do_debug_exception) here. > >> > >> Assuming so, and with that fixed up: > >> > >> Acked-by: Mark Rutland <mark.rutland@arm.com> > > > > Good catch, if so, this looks good to me too. > > I should have noted it in the commit message, but the NOKPROBE_SYMBOL(do_debug_exception) > is already there! Added by commit 2dd0e8d2d2a15 ("arm64: Kprobes with single stepping > support"). > > (kprobing the debug handler is so bad, we blacklist it twice!) Ah; neat! > I'll fix the commit message. > > > > with that fixed up: > > > > Acked-by: Masami Hiramatsu <mhiramat@kernel.org> > > I assume you're both happy for me to apply these tags. Certainly! Mark.
diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index a17393ff6677..b0b3ba56e919 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -8,14 +8,14 @@ #define __ASM_EXCEPTION_H #include <asm/esr.h> +#include <asm/kprobes.h> #include <linux/interrupt.h> -#define __exception __attribute__((section(".exception.text"))) #ifdef CONFIG_FUNCTION_GRAPH_TRACER #define __exception_irq_entry __irq_entry #else -#define __exception_irq_entry __exception +#define __exception_irq_entry __kprobes #endif static inline u32 disr_to_esr(u64 disr) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index 59690613ac31..cee5928e1b7d 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -42,16 +42,6 @@ static inline int __in_irqentry_text(unsigned long ptr) ptr < (unsigned long)&__irqentry_text_end; } -static inline int in_exception_text(unsigned long ptr) -{ - int in; - - in = ptr >= (unsigned long)&__exception_text_start && - ptr < (unsigned long)&__exception_text_end; - - return in ? : __in_irqentry_text(ptr); -} - static inline int in_entry_text(unsigned long ptr) { return ptr >= (unsigned long)&__entry_text_start && diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index c4452827419b..d1c95dcf1d78 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -455,10 +455,6 @@ int __init arch_populate_kprobe_blacklist(void) (unsigned long)__irqentry_text_end); if (ret) return ret; - ret = kprobe_add_area_blacklist((unsigned long)__exception_text_start, - (unsigned long)__exception_text_end); - if (ret) - return ret; ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start, (unsigned long)__idmap_text_end); if (ret) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 34739e80211b..ba1a571a7774 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -35,6 +35,7 @@ #include <asm/debug-monitors.h> #include <asm/esr.h> #include <asm/insn.h> +#include <asm/kprobes.h> #include <asm/traps.h> #include <asm/smp.h> #include <asm/stack_pointer.h> @@ -393,7 +394,7 @@ void arm64_notify_segfault(unsigned long addr) force_signal_inject(SIGSEGV, code, addr); } -asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +asmlinkage void do_undefinstr(struct pt_regs *regs) { /* check for AArch32 breakpoint instructions */ if (!aarch32_break_handler(regs)) @@ -405,6 +406,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) BUG_ON(!user_mode(regs)); force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); } +NOKPROBE_SYMBOL(do_undefinstr); #define __user_cache_maint(insn, address, res) \ if (address >= user_addr_max()) { \ @@ -667,7 +669,7 @@ static const struct sys64_hook cp15_64_hooks[] = { {}, }; -asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs) +asmlinkage void do_cp15instr(unsigned int esr, struct pt_regs *regs) { const struct sys64_hook *hook, *hook_base; @@ -705,9 +707,10 @@ asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs) */ do_undefinstr(regs); } +NOKPROBE_SYMBOL(do_cp15instr); #endif -asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs) +asmlinkage void do_sysinstr(unsigned int esr, struct pt_regs *regs) { const struct sys64_hook *hook; @@ -724,6 +727,7 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs) */ do_undefinstr(regs); } +NOKPROBE_SYMBOL(do_sysinstr); static const char *esr_class_str[] = { [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC", diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index aa76f7259668..009057517bdd 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -111,9 +111,6 @@ SECTIONS } .text : { /* Real text segment */ _stext = .; /* Text and read-only data */ - __exception_text_start = .; - *(.exception.text) - __exception_text_end = .; IRQENTRY_TEXT SOFTIRQENTRY_TEXT ENTRY_TEXT diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 115d7a0e4b08..ba62098de920 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -33,6 +33,7 @@ #include <asm/debug-monitors.h> #include <asm/esr.h> #include <asm/kasan.h> +#include <asm/kprobes.h> #include <asm/sysreg.h> #include <asm/system_misc.h> #include <asm/pgtable.h> @@ -723,8 +724,8 @@ static const struct fault_info fault_info[] = { { do_bad, SIGKILL, SI_KERNEL, "unknown 63" }, }; -asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, - struct pt_regs *regs) +asmlinkage void do_mem_abort(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { const struct fault_info *inf = esr_to_fault_info(esr); @@ -740,16 +741,17 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, arm64_notify_die(inf->name, regs, inf->sig, inf->code, (void __user *)addr, esr); } +NOKPROBE_SYMBOL(do_mem_abort); -asmlinkage void __exception do_el0_irq_bp_hardening(void) +asmlinkage void do_el0_irq_bp_hardening(void) { /* PC has already been checked in entry.S */ arm64_apply_bp_hardening(); } +NOKPROBE_SYMBOL(do_el0_irq_bp_hardening); -asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr, - unsigned int esr, - struct pt_regs *regs) +asmlinkage void do_el0_ia_bp_hardening(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { /* * We've taken an instruction abort from userspace and not yet @@ -762,11 +764,10 @@ asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr, local_daif_restore(DAIF_PROCCTX); do_mem_abort(addr, esr, regs); } +NOKPROBE_SYMBOL(do_el0_ia_bp_hardening); - -asmlinkage void __exception do_sp_pc_abort(unsigned long addr, - unsigned int esr, - struct pt_regs *regs) +asmlinkage void do_sp_pc_abort(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { if (user_mode(regs)) { if (!is_ttbr0_addr(instruction_pointer(regs))) @@ -777,6 +778,7 @@ asmlinkage void __exception do_sp_pc_abort(unsigned long addr, arm64_notify_die("SP/PC alignment exception", regs, SIGBUS, BUS_ADRALN, (void __user *)addr, esr); } +NOKPROBE_SYMBOL(do_sp_pc_abort); int __init early_brk64(unsigned long addr, unsigned int esr, struct pt_regs *regs); @@ -859,8 +861,7 @@ NOKPROBE_SYMBOL(debug_exception_exit); #ifdef CONFIG_ARM64_ERRATUM_1463225 DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa); -static int __exception -cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) +static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) { if (user_mode(regs)) return 0; @@ -879,16 +880,15 @@ cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) return 1; } #else -static int __exception -cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) +static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) { return 0; } #endif /* CONFIG_ARM64_ERRATUM_1463225 */ +NOKPROBE_SYMBOL(cortex_a76_erratum_1463225_debug_handler); -asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint, - unsigned int esr, - struct pt_regs *regs) +asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint, + unsigned int esr, struct pt_regs *regs) { const struct fault_info *inf = esr_to_debug_fault_info(esr); unsigned long pc = instruction_pointer(regs);
Since commit 732674980139 ("arm64: unwind: reference pt_regs via embedded stack frame") arm64 has has not used the __exception annotation to dump the pt_regs during stack tracing. in_exception_text() has no callers. This annotation is only used to blacklist kprobes, it means the same as __kprobes. Section annotations like this require the functions to be grouped together between the start/end markers, and placed according to the linker script. For kprobes we also have NOKPROBE_SYMBOL() which logs the symbol address in a section that kprobes parses and blacklists at boot. Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of blacklisted symbols, and saves us from having an arm64 specific spelling of __kprobes. Signed-off-by: James Morse <james.morse@arm.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> --- (__exception_irq_entry means no-kprobes and optionally in a section ftrace can use to pretty-print interrupt handler boundaries.) --- arch/arm64/include/asm/exception.h | 4 ++-- arch/arm64/include/asm/traps.h | 10 --------- arch/arm64/kernel/probes/kprobes.c | 4 ---- arch/arm64/kernel/traps.c | 10 ++++++--- arch/arm64/kernel/vmlinux.lds.S | 3 --- arch/arm64/mm/fault.c | 34 +++++++++++++++--------------- 6 files changed, 26 insertions(+), 39 deletions(-)