Messages in this thread Patch in this message |  | | Date | Wed, 04 Dec 2013 19:51:04 +0200 | From | Taras Kondratiuk <> | Subject | Re: [PATCH v3 00/15] uprobes: Add uprobes support for ARM |
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On 11/27/2013 04:53 AM, David Long wrote: > From: "David A. Long" <dave.long@linaro.org> > > This patch series adds basic uprobes support to ARM. It is based on patches > developed earlier by Rabin Vincent. That approach of adding hooks into > the kprobes instruction parsing code was not well received. This approach > separates the ARM instruction parsing code in kprobes out into a separate set > of functions which can be used by both kprobes and uprobes. Both kprobes and > uprobes then provide their own semantic action tables to process the results of > the parsing. > > The following are noteworthy changes made for v3: > > 1) The ARM uprobes functionality no longer depends on kprobes. As > a side effect of this there are no longer any changes to the common > kprobes include file (or any other common kprobes files). > 2) A couple large patches have been broken down into more smaller > patches. > 3) A problem with uretprobes has been fixed. > 4) The kprobes-test module has been made more useable for thumb tests. > 5) The argument list to the "action" functions has been shrunk. > 6) Alignment with a few recent patches that were made to common > uprobes code specifically to support this patchset. > > This patchset is based on v3.13-rc1
Hi Dave
I've tested this series in big-endian mode. There is an issue within __create_xol_area() function. It writes UPROBE_SWBP_INSN directly to memory, but UPROBE_SWBP_INSN stores canonical opcode, which leads to a wrong instruction endianness if CPU runs in BE.
I think the easies way to fix it without touching generic uprobes code is to store opcode in native endianness in UPROBE_SWBP_INSN, and use another macro for canonical form in ARM specific code. Please check a diff below. With this diff plus addressed comment for patch 14/15 plus fixed Ben's BE kprobes series I have uprobes working on LE and BE.
diff --git a/arch/arm/include/asm/uprobes.h b/arch/arm/include/asm/uprobes.h index e5acaa3..5313418 100644 --- a/arch/arm/include/asm/uprobes.h +++ b/arch/arm/include/asm/uprobes.h @@ -2,14 +2,16 @@ #define _ASM_UPROBES_H #include <asm/probes.h> +#include <asm/opcodes.h> typedef u32 uprobe_opcode_t; #define MAX_UINSN_BYTES 4 #define UPROBE_XOL_SLOT_BYTES 64 -#define UPROBE_SWBP_INSN 0xe7f001f9 -#define UPROBE_SS_INSN 0xe7f001fa +#define UPROBE_SWBP_ARM_INSN 0xe7f001f9 +#define UPROBE_SS_ARM_INSN 0xe7f001fa +#define UPROBE_SWBP_INSN __opcode_to_mem_arm(UPROBE_SWBP_ARM_INSN) #define UPROBE_SWBP_INSN_SIZE 4 struct arch_uprobe_task { diff --git a/arch/arm/kernel/uprobes.c b/arch/arm/kernel/uprobes.c index d9873ef..ae18549 100644 --- a/arch/arm/kernel/uprobes.c +++ b/arch/arm/kernel/uprobes.c @@ -22,7 +22,7 @@ bool is_swbp_insn(uprobe_opcode_t *insn) { return (__mem_to_opcode_arm(*insn) & 0x0fffffff) == - (UPROBE_SWBP_INSN & 0x0fffffff); + (UPROBE_SWBP_ARM_INSN & 0x0fffffff); } int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, @@ -83,7 +83,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn); auprobe->ixol[0] = __opcode_to_mem_arm(insn); - auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_INSN); + auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN); ret = arm_probes_decode_insn(insn, &auprobe->asi, false, uprobes_probes_actions); @@ -100,7 +100,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, break; } - bpinsn = UPROBE_SWBP_INSN & 0x0fffffff; + bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff; if (insn >= 0xe0000000) bpinsn |= 0xe0000000; /* Unconditional instruction */ else @@ -158,9 +158,9 @@ static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr) local_irq_save(flags); instr &= 0x0fffffff; - if (instr == (UPROBE_SWBP_INSN & 0x0fffffff)) + if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff)) uprobe_pre_sstep_notifier(regs); - else if (instr == (UPROBE_SS_INSN & 0x0fffffff)) + else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff)) uprobe_post_sstep_notifier(regs); local_irq_restore(flags); @@ -174,7 +174,7 @@ unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) static struct undef_hook uprobes_arm_break_hook = { .instr_mask = 0x0fffffff, - .instr_val = (UPROBE_SWBP_INSN & 0x0fffffff), + .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff), .cpsr_mask = MODE_MASK, .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, @@ -182,7 +182,7 @@ static struct undef_hook uprobes_arm_break_hook = { static struct undef_hook uprobes_arm_ss_hook = { .instr_mask = 0x0fffffff, - .instr_val = (UPROBE_SS_INSN & 0x0fffffff), + .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff), .cpsr_mask = MODE_MASK, .cpsr_val = USR_MODE, .fn = uprobe_trap_handler,
-- Taras Kondratiuk
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