Re: [4/6 PATCH] Kprobes : Prevent possible race conditions ppc64 changes

From: Ananth N Mavinakayanahalli
Date: Fri Jul 08 2005 - 09:15:26 EST

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On Thu, Jul 07, 2005 at 03:46:50PM +0530, Prasanna S Panchamukhi wrote:
>
> This patch contains the ppc64 architecture specific changes to
> prevent the possible race conditions.

Prasanna,

Please cc or post this patch to linuxppc64-dev@xxxxxxxxxxx This patch
touches files I am not sure I can comment on with authority.

Thanks,
Ananth

>
> Signed-off-by: Prasanna S Panchamukhi <prasanna@xxxxxxxxxx>
>
>
> ---
>
> linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/kprobes.c | 29 +++++-----
> linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/misc.S | 4 -
> linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/traps.c | 5 +
> linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/vmlinux.lds.S | 1
> linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/mm/fault.c | 5 +
> linux-2.6.13-rc1-mm1-prasanna/include/asm-ppc64/processor.h | 14 ++++
> 6 files changed, 38 insertions(+), 20 deletions(-)
>
> diff -puN arch/ppc64/kernel/kprobes.c~kprobes-exclude-functions-ppc64 arch/ppc64/kernel/kprobes.c
> --- linux-2.6.13-rc1-mm1/arch/ppc64/kernel/kprobes.c~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/kprobes.c 2005-07-06 20:07:22.000000000 +0530
> @@ -44,7 +44,7 @@ static struct kprobe *kprobe_prev;
> static unsigned long kprobe_status_prev, kprobe_saved_msr_prev;
> static struct pt_regs jprobe_saved_regs;
>
> -int arch_prepare_kprobe(struct kprobe *p)
> +int __kprobes arch_prepare_kprobe(struct kprobe *p)
> {
> int ret = 0;
> kprobe_opcode_t insn = *p->addr;
> @@ -68,27 +68,27 @@ int arch_prepare_kprobe(struct kprobe *p
> return ret;
> }
>
> -void arch_copy_kprobe(struct kprobe *p)
> +void __kprobes arch_copy_kprobe(struct kprobe *p)
> {
> memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
> p->opcode = *p->addr;
> }
>
> -void arch_arm_kprobe(struct kprobe *p)
> +void __kprobes arch_arm_kprobe(struct kprobe *p)
> {
> *p->addr = BREAKPOINT_INSTRUCTION;
> flush_icache_range((unsigned long) p->addr,
> (unsigned long) p->addr + sizeof(kprobe_opcode_t));
> }
>
> -void arch_disarm_kprobe(struct kprobe *p)
> +void __kprobes arch_disarm_kprobe(struct kprobe *p)
> {
> *p->addr = p->opcode;
> flush_icache_range((unsigned long) p->addr,
> (unsigned long) p->addr + sizeof(kprobe_opcode_t));
> }
>
> -void arch_remove_kprobe(struct kprobe *p)
> +void __kprobes arch_remove_kprobe(struct kprobe *p)
> {
> up(&kprobe_mutex);
> free_insn_slot(p->ainsn.insn);
> @@ -122,7 +122,8 @@ static inline void restore_previous_kpro
> kprobe_saved_msr = kprobe_saved_msr_prev;
> }
>
> -void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)
> +void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
> + struct pt_regs *regs)
> {
> struct kretprobe_instance *ri;
>
> @@ -244,7 +245,7 @@ void kretprobe_trampoline_holder(void)
> /*
> * Called when the probe at kretprobe trampoline is hit
> */
> -int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
> +int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
> {
> struct kretprobe_instance *ri = NULL;
> struct hlist_head *head;
> @@ -308,7 +309,7 @@ int trampoline_probe_handler(struct kpro
> * single-stepped a copy of the instruction. The address of this
> * copy is p->ainsn.insn.
> */
> -static void resume_execution(struct kprobe *p, struct pt_regs *regs)
> +static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
> {
> int ret;
> unsigned int insn = *p->ainsn.insn;
> @@ -373,8 +374,8 @@ static inline int kprobe_fault_handler(s
> /*
> * Wrapper routine to for handling exceptions.
> */
> -int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
> - void *data)
> +int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
> + unsigned long val, void *data)
> {
> struct die_args *args = (struct die_args *)data;
> int ret = NOTIFY_DONE;
> @@ -406,7 +407,7 @@ int kprobe_exceptions_notify(struct noti
> return ret;
> }
>
> -int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
> +int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
> {
> struct jprobe *jp = container_of(p, struct jprobe, kp);
>
> @@ -419,16 +420,16 @@ int setjmp_pre_handler(struct kprobe *p,
> return 1;
> }
>
> -void jprobe_return(void)
> +void __kprobes jprobe_return(void)
> {
> asm volatile("trap" ::: "memory");
> }
>
> -void jprobe_return_end(void)
> +void __kprobes jprobe_return_end(void)
> {
> };
>
> -int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
> +int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
> {
> /*
> * FIXME - we should ideally be validating that we got here 'cos
> diff -puN arch/ppc64/kernel/traps.c~kprobes-exclude-functions-ppc64 arch/ppc64/kernel/traps.c
> --- linux-2.6.13-rc1-mm1/arch/ppc64/kernel/traps.c~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/traps.c 2005-07-06 20:07:22.000000000 +0530
> @@ -30,6 +30,7 @@
> #include <linux/init.h>
> #include <linux/module.h>
> #include <linux/delay.h>
> +#include <linux/kprobes.h>
> #include <asm/kdebug.h>
>
> #include <asm/pgtable.h>
> @@ -220,7 +221,7 @@ void instruction_breakpoint_exception(st
> _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
> }
>
> -void single_step_exception(struct pt_regs *regs)
> +void __kprobes single_step_exception(struct pt_regs *regs)
> {
> regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
>
> @@ -398,7 +399,7 @@ check_bug_trap(struct pt_regs *regs)
> return 0;
> }
>
> -void program_check_exception(struct pt_regs *regs)
> +void __kprobes program_check_exception(struct pt_regs *regs)
> {
> if (debugger_fault_handler(regs))
> return;
> diff -puN arch/ppc64/kernel/vmlinux.lds.S~kprobes-exclude-functions-ppc64 arch/ppc64/kernel/vmlinux.lds.S
> --- linux-2.6.13-rc1-mm1/arch/ppc64/kernel/vmlinux.lds.S~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/vmlinux.lds.S 2005-07-06 20:07:22.000000000 +0530
> @@ -15,6 +15,7 @@ SECTIONS
> *(.text .text.*)
> SCHED_TEXT
> LOCK_TEXT
> + KPROBES_TEXT
> *(.fixup)
> . = ALIGN(4096);
> _etext = .;
> diff -puN arch/ppc64/mm/fault.c~kprobes-exclude-functions-ppc64 arch/ppc64/mm/fault.c
> --- linux-2.6.13-rc1-mm1/arch/ppc64/mm/fault.c~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/mm/fault.c 2005-07-06 20:07:22.000000000 +0530
> @@ -29,6 +29,7 @@
> #include <linux/interrupt.h>
> #include <linux/smp_lock.h>
> #include <linux/module.h>
> +#include <linux/kprobes.h>
>
> #include <asm/page.h>
> #include <asm/pgtable.h>
> @@ -84,8 +85,8 @@ static int store_updates_sp(struct pt_re
> * The return value is 0 if the fault was handled, or the signal
> * number if this is a kernel fault that can't be handled here.
> */
> -int do_page_fault(struct pt_regs *regs, unsigned long address,
> - unsigned long error_code)
> +int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
> + unsigned long error_code)
> {
> struct vm_area_struct * vma;
> struct mm_struct *mm = current->mm;
> diff -puN arch/ppc64/kernel/misc.S~kprobes-exclude-functions-ppc64 arch/ppc64/kernel/misc.S
> --- linux-2.6.13-rc1-mm1/arch/ppc64/kernel/misc.S~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/arch/ppc64/kernel/misc.S 2005-07-07 10:24:00.000000000 +0530
> @@ -183,7 +183,7 @@ PPC64_CACHES:
> * flush all bytes from start through stop-1 inclusive
> */
>
> -_GLOBAL(__flush_icache_range)
> +_KPROBE(__flush_icache_range)
>
> /*
> * Flush the data cache to memory
> @@ -223,7 +223,7 @@ _GLOBAL(__flush_icache_range)
> bdnz 2b
> isync
> blr
> -
> + .previous .text
> /*
> * Like above, but only do the D-cache.
> *
> diff -puN include/asm-ppc64/processor.h~kprobes-exclude-functions-ppc64 include/asm-ppc64/processor.h
> --- linux-2.6.13-rc1-mm1/include/asm-ppc64/processor.h~kprobes-exclude-functions-ppc64 2005-07-06 20:07:22.000000000 +0530
> +++ linux-2.6.13-rc1-mm1-prasanna/include/asm-ppc64/processor.h 2005-07-07 10:22:29.000000000 +0530
> @@ -309,6 +309,20 @@ name: \
> .type GLUE(.,name),@function; \
> GLUE(.,name):
>
> +#define _KPROBE(name) \
> + .section ".kprobes.text","a"; \
> + .align 2 ; \
> + .globl name; \
> + .globl GLUE(.,name); \
> + .section ".opd","aw"; \
> +name: \
> + .quad GLUE(.,name); \
> + .quad .TOC.@tocbase; \
> + .quad 0; \
> + .previous; \
> + .type GLUE(.,name),@function; \
> +GLUE(.,name):
> +
> #define _STATIC(name) \
> .section ".text"; \
> .align 2 ; \
>
> _
> --
>
> Prasanna S Panchamukhi
> Linux Technology Center
> India Software Labs, IBM Bangalore
> Ph: 91-80-25044636
> <prasanna@xxxxxxxxxx>
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Next message: Miklos Szeredi: "Re: [RFC PATCH 1/8] share/private/slave a subtree"
Previous message: Daniel Walker: "Re: 'sleeping function called from invalid context' bug whenmounting an IDE device"
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