arm64: remove __exception annotations

Since commit 732674980139 ("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: James Morse <james.morse@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index a17393f..b0b3ba5 100644 (file)
--- 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 5969061..cee5928 100644 (file)
--- 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 c445282..d1c95dc 100644 (file)
--- 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 34739e8..ba1a571 100644 (file)
--- 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 aa76f72..0090575 100644 (file)
--- 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 855f2a7..844cd25 100644 (file)
--- 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>
@@ -732,8 +733,8 @@ 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);
 
@@ -749,16 +750,17 @@ 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
@@ -771,11 +773,10 @@ 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)))
@@ -786,6 +787,7 @@ 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);
@@ -868,8 +870,7 @@ 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;
@@ -888,16 +889,15 @@ 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);