| Message ID | a04c2ba0-88f7-17af-8c2f-8fda8569ec13@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
Balbir Singh <bsingharora@gmail.com> writes: > This patch is tied to xmon, it can be refactored out > better later if required. The idea is to provide > disassembly using xmon so that when we get an OOPS > we see something like the following below > > ... > NIP [c00000000063a230] lkdtm_WARNING+0x0/0x10 > LR [c00000000063986c] lkdtm_do_action+0x3c/0x80 > Call Trace: > [c0000000ef1bbbc0] [c0000000009a5804] printk+0x50/0x64 (unreliable) > [c0000000ef1bbbe0] [c000000000639cc0] direct_entry+0x100/0x1b0 > [c0000000ef1bbc70] [c00000000043eb4c] full_proxy_write+0x8c/0x100 > [c0000000ef1bbcd0] [c00000000028fe24] __vfs_write+0x54/0x1c0 > [c0000000ef1bbd80] [c000000000291138] vfs_write+0xc8/0x260 > [c0000000ef1bbdd0] [c000000000292c98] SyS_write+0x78/0x120 > [c0000000ef1bbe30] [c00000000000b220] system_call+0x38/0xfc > Instruction dump: > c00000000063a200 38630618 addi r3,r3,1560 > c00000000063a204 f8010010 std r0,16(r1) > c00000000063a208 f821ffa1 stdu r1,-96(r1) > c00000000063a20c 4836b0f1 bl c0000000009a52fc# panic+0x8/0x304 > c00000000063a210 60000000 nop > c00000000063a214 60000000 nop > c00000000063a218 60000000 nop > c00000000063a21c 60420000 ori r2,r2,0 > c00000000063a220 0fe00000 twi 31,r0,0 > c00000000063a224 60000000 nop > c00000000063a228 60000000 nop > c00000000063a22c 60420000 ori r2,r2,0 > c00000000063a230 0fe00000 twi 31,r0,0 > ^^^^^^^^ > NOTE: That the <> around the instruction that caused the > OOPS is now replaced with a ^^^^ following the disassembly > in the output. I think I'd prefer: c00000000063a22c 60420000 ori r2,r2,0 c00000000063a230 0fe00000 twi 31,r0,0 # <- nip c00000000063a234 4e800020 blr Or maybe: c00000000063a22c 60420000 ori r2,r2,0 c00000000063a230 0fe00000 twi 31,r0,0 # Faulting instruction c00000000063a234 4e800020 blr ? > An issue was raised if as to whether calling > xmon during OOPS can cause further issues? xmon has been used > robustly in the past to look at OOPS and disassemble them > and moreover the OOPS output is at the end, so we've already > captured the GPR's and stack trace already. Once it's refactored properly you won't be calling xmon at all, you'll just be calling the disassembly code. The problem we have is that currently print_insn_powerpc() is built using nonstdio.h, which means it is calling xmon_printf(), and that's not what we want to do for an oops. An oops is printed using printk. So that will need more work. > NOTE2: If CONFIG_XMON_DISASSEMBLY is turned off, the disassembly > will be printed as a list of .long(s). It is highly recommended > to have both CONFIG_XMON_DISASSEMBLY and CONFIG_XMON for usable > output. So once it's refactored CONFIG_XMON_DISASSEMBLY would become CONFIG_PPC_DISASSEMBLY (or something like that), and there'd be no dependency on CONFIG_XMON. And so there'd be no fallback to printing longs, you'd either print the old compact format, or the disassembled format. cheers
diff --git a/arch/powerpc/include/asm/xmon.h b/arch/powerpc/include/asm/xmon.h index 5eb8e59..cd4c0cd 100644 --- a/arch/powerpc/include/asm/xmon.h +++ b/arch/powerpc/include/asm/xmon.h @@ -20,6 +20,7 @@ extern void xmon_register_spus(struct list_head *list); struct pt_regs; extern int xmon(struct pt_regs *excp); extern irqreturn_t xmon_irq(int, void *); +extern int ppc_inst_dump(unsigned long addr, long count, int praddr); #else static inline void xmon_setup(void) { }; static inline void xmon_register_spus(struct list_head *list) { }; diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 04885ce..2a235bf 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -52,6 +52,7 @@ #include <asm/switch_to.h> #include <asm/tm.h> #include <asm/debug.h> +#include <asm/xmon.h> #ifdef CONFIG_PPC64 #include <asm/firmware.h> #endif @@ -1217,10 +1218,20 @@ static void show_instructions(struct pt_regs *regs) probe_kernel_address((unsigned int __user *)pc, instr)) { pr_cont("XXXXXXXX "); } else { +#ifndef CONFIG_XMON if (regs->nip == pc) pr_cont("<%08x> ", instr); else pr_cont("%08x ", instr); +#else + /* Does not work for SPU's */ + ppc_inst_dump(pc, 1, 1); + if (regs->nip == pc) + /* + * 26 = 16 (addr) + 2 (spaces) + 8 (instr) + */ + printk("%*s\n", 26, "^^^^^^^^"); +#endif } pc += sizeof(int); diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 9c0e17c..ceb7a05 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -123,7 +123,6 @@ static void memex(void); static int bsesc(void); static void dump(void); static void prdump(unsigned long, long); -static int ppc_inst_dump(unsigned long, long, int); static void dump_log_buf(void); #ifdef CONFIG_PPC_POWERNV @@ -2471,7 +2470,7 @@ generic_inst_dump(unsigned long adr, long count, int praddr, return adr - first_adr; } -static int +int ppc_inst_dump(unsigned long adr, long count, int praddr) { return generic_inst_dump(adr, count, praddr, print_insn_powerpc);
This patch is tied to xmon, it can be refactored out better later if required. The idea is to provide disassembly using xmon so that when we get an OOPS we see something like the following below ... NIP [c00000000063a230] lkdtm_WARNING+0x0/0x10 LR [c00000000063986c] lkdtm_do_action+0x3c/0x80 Call Trace: [c0000000ef1bbbc0] [c0000000009a5804] printk+0x50/0x64 (unreliable) [c0000000ef1bbbe0] [c000000000639cc0] direct_entry+0x100/0x1b0 [c0000000ef1bbc70] [c00000000043eb4c] full_proxy_write+0x8c/0x100 [c0000000ef1bbcd0] [c00000000028fe24] __vfs_write+0x54/0x1c0 [c0000000ef1bbd80] [c000000000291138] vfs_write+0xc8/0x260 [c0000000ef1bbdd0] [c000000000292c98] SyS_write+0x78/0x120 [c0000000ef1bbe30] [c00000000000b220] system_call+0x38/0xfc Instruction dump: c00000000063a200 38630618 addi r3,r3,1560 c00000000063a204 f8010010 std r0,16(r1) c00000000063a208 f821ffa1 stdu r1,-96(r1) c00000000063a20c 4836b0f1 bl c0000000009a52fc# panic+0x8/0x304 c00000000063a210 60000000 nop c00000000063a214 60000000 nop c00000000063a218 60000000 nop c00000000063a21c 60420000 ori r2,r2,0 c00000000063a220 0fe00000 twi 31,r0,0 c00000000063a224 60000000 nop c00000000063a228 60000000 nop c00000000063a22c 60420000 ori r2,r2,0 c00000000063a230 0fe00000 twi 31,r0,0 ^^^^^^^^ c00000000063a234 4e800020 blr c00000000063a238 60000000 nop c00000000063a23c 60420000 ori r2,r2,0 ---[ end trace 4def3909e4288c1c ]--- NOTE: That the <> around the instruction that caused the OOPS is now replaced with a ^^^^ following the disassembly in the output. An issue was raised if as to whether calling xmon during OOPS can cause further issues? xmon has been used robustly in the past to look at OOPS and disassemble them and moreover the OOPS output is at the end, so we've already captured the GPR's and stack trace already. NOTE2: If CONFIG_XMON_DISASSEMBLY is turned off, the disassembly will be printed as a list of .long(s). It is highly recommended to have both CONFIG_XMON_DISASSEMBLY and CONFIG_XMON for usable output. Signed-off-by: Balbir Singh <bsingharora@gmail.com> --- arch/powerpc/include/asm/xmon.h | 1 + arch/powerpc/kernel/process.c | 11 +++++++++++ arch/powerpc/xmon/xmon.c | 3 +-- 3 files changed, 13 insertions(+), 2 deletions(-)