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    Subject[tip:x86/cleanups] x86/dumpstack: Add a show_ip() function
    Commit-ID:  7cccf0725cf7402514e09c52b089430005798b7f
    Gitweb: https://git.kernel.org/tip/7cccf0725cf7402514e09c52b089430005798b7f
    Author: Borislav Petkov <bp@suse.de>
    AuthorDate: Tue, 17 Apr 2018 18:11:22 +0200
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Thu, 26 Apr 2018 16:15:27 +0200

    x86/dumpstack: Add a show_ip() function

    ... which shows the Instruction Pointer along with the insn bytes around
    it. Use it whenever rIP is printed. Drop the rIP < PAGE_OFFSET check since
    probe_kernel_read() can handle any address properly.

    Signed-off-by: Borislav Petkov <bp@suse.de>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Link: https://lkml.kernel.org/r/20180417161124.5294-8-bp@alien8.de

    ---
    arch/x86/include/asm/stacktrace.h | 1 +
    arch/x86/kernel/dumpstack.c | 23 +++++++++++++----------
    arch/x86/kernel/process_32.c | 8 +++-----
    3 files changed, 17 insertions(+), 15 deletions(-)

    diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
    index 0630eeb18bbc..b6dc698f992a 100644
    --- a/arch/x86/include/asm/stacktrace.h
    +++ b/arch/x86/include/asm/stacktrace.h
    @@ -112,4 +112,5 @@ static inline unsigned long caller_frame_pointer(void)
    }

    void show_opcodes(u8 *rip, const char *loglvl);
    +void show_ip(struct pt_regs *regs, const char *loglvl);
    #endif /* _ASM_X86_STACKTRACE_H */
    diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
    index 1592d0c3ebb5..82da808b5c36 100644
    --- a/arch/x86/kernel/dumpstack.c
    +++ b/arch/x86/kernel/dumpstack.c
    @@ -94,9 +94,19 @@ void show_opcodes(u8 *rip, const char *loglvl)
    pr_cont("\n");
    }

    +void show_ip(struct pt_regs *regs, const char *loglvl)
    +{
    +#ifdef CONFIG_X86_32
    + printk("%sEIP: %pS\n", loglvl, (void *)regs->ip);
    +#else
    + printk("%sRIP: %04x:%pS\n", loglvl, (int)regs->cs, (void *)regs->ip);
    +#endif
    + show_opcodes((u8 *)regs->ip, loglvl);
    +}
    +
    void show_iret_regs(struct pt_regs *regs)
    {
    - printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip);
    + show_ip(regs, KERN_DEFAULT);
    printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss,
    regs->sp, regs->flags);
    }
    @@ -392,15 +402,8 @@ void show_regs(struct pt_regs *regs)
    __show_regs(regs, all);

    /*
    - * When in-kernel, we also print out the stack and code at the
    - * time of the fault..
    + * When in-kernel, we also print out the stack at the time of the fault..
    */
    - if (!user_mode(regs)) {
    + if (!user_mode(regs))
    show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
    -
    - if (regs->ip < PAGE_OFFSET)
    - printk(KERN_DEFAULT "Code: Bad RIP value.\n");
    - else
    - show_opcodes((u8 *)regs->ip, KERN_DEFAULT);
    - }
    }
    diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
    index 5224c6099184..0ae659de21eb 100644
    --- a/arch/x86/kernel/process_32.c
    +++ b/arch/x86/kernel/process_32.c
    @@ -76,16 +76,14 @@ void __show_regs(struct pt_regs *regs, int all)
    savesegment(gs, gs);
    }

    - printk(KERN_DEFAULT "EIP: %pS\n", (void *)regs->ip);
    - printk(KERN_DEFAULT "EFLAGS: %08lx CPU: %d\n", regs->flags,
    - raw_smp_processor_id());
    + show_ip(regs, KERN_DEFAULT);

    printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
    regs->ax, regs->bx, regs->cx, regs->dx);
    printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
    regs->si, regs->di, regs->bp, sp);
    - printk(KERN_DEFAULT " DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n",
    - (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss);
    + printk(KERN_DEFAULT "DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x EFLAGS: %08lx\n",
    + (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss, regs->flags);

    if (!all)
    return;
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