Commit b6e43c0e authored by James Morse's avatar James Morse Committed by Catalin Marinas
Browse files

arm64: remove __exception annotations 



Since commit 73267498 ("arm64: unwind: reference pt_regs via embedded
stack frame") arm64 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.

do_debug_exception() already has a NOKPROBE_SYMBOL() annotation.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 4f5cafb5

arch/arm64/include/asm/exception.h

+2 −2
Original line number Diff line number Diff line
@@ -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)

arch/arm64/include/asm/traps.h

+0 −10
Original line number Diff line number Diff line
@@ -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 &&

arch/arm64/kernel/probes/kprobes.c

+0 −4
Original line number Diff line number Diff line
@@ -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)

arch/arm64/kernel/traps.c

+7 −3
Original line number Diff line number Diff line
@@ -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",

arch/arm64/kernel/vmlinux.lds.S

+0 −3
Original line number Diff line number Diff line
@@ -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

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