diff options
Diffstat (limited to 'arch/arm/kernel/ftrace.c')
| -rw-r--r-- | arch/arm/kernel/ftrace.c | 100 |
1 files changed, 28 insertions, 72 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index c0062ad1e84..df0bf0c8cb7 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -16,10 +16,13 @@ #include <linux/uaccess.h> #include <asm/cacheflush.h> +#include <asm/opcodes.h> #include <asm/ftrace.h> +#include "insn.h" + #ifdef CONFIG_THUMB2_KERNEL -#define NOP 0xeb04f85d /* pop.w {lr} */ +#define NOP 0xf85deb04 /* pop.w {lr} */ #else #define NOP 0xe8bd4000 /* pop {lr} */ #endif @@ -60,76 +63,31 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr) } #endif -#ifdef CONFIG_THUMB2_KERNEL -static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, - bool link) -{ - unsigned long s, j1, j2, i1, i2, imm10, imm11; - unsigned long first, second; - long offset; - - offset = (long)addr - (long)(pc + 4); - if (offset < -16777216 || offset > 16777214) { - WARN_ON_ONCE(1); - return 0; - } - - s = (offset >> 24) & 0x1; - i1 = (offset >> 23) & 0x1; - i2 = (offset >> 22) & 0x1; - imm10 = (offset >> 12) & 0x3ff; - imm11 = (offset >> 1) & 0x7ff; - - j1 = (!i1) ^ s; - j2 = (!i2) ^ s; - - first = 0xf000 | (s << 10) | imm10; - second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11; - if (link) - second |= 1 << 14; - - return (second << 16) | first; -} -#else -static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, - bool link) -{ - unsigned long opcode = 0xea000000; - long offset; - - if (link) - opcode |= 1 << 24; - - offset = (long)addr - (long)(pc + 8); - if (unlikely(offset < -33554432 || offset > 33554428)) { - /* Can't generate branches that far (from ARM ARM). Ftrace - * doesn't generate branches outside of kernel text. - */ - WARN_ON_ONCE(1); - return 0; - } - - offset = (offset >> 2) & 0x00ffffff; - - return opcode | offset; -} -#endif - static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) { - return ftrace_gen_branch(pc, addr, true); + return arm_gen_branch_link(pc, addr); } static int ftrace_modify_code(unsigned long pc, unsigned long old, - unsigned long new) + unsigned long new, bool validate) { unsigned long replaced; - if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE)) - return -EFAULT; + if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) { + old = __opcode_to_mem_thumb32(old); + new = __opcode_to_mem_thumb32(new); + } else { + old = __opcode_to_mem_arm(old); + new = __opcode_to_mem_arm(new); + } - if (replaced != old) - return -EINVAL; + if (validate) { + if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE)) + return -EFAULT; + + if (replaced != old) + return -EINVAL; + } if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE)) return -EPERM; @@ -141,23 +99,21 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old, int ftrace_update_ftrace_func(ftrace_func_t func) { - unsigned long pc, old; + unsigned long pc; unsigned long new; int ret; pc = (unsigned long)&ftrace_call; - memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE); new = ftrace_call_replace(pc, (unsigned long)func); - ret = ftrace_modify_code(pc, old, new); + ret = ftrace_modify_code(pc, 0, new, false); #ifdef CONFIG_OLD_MCOUNT if (!ret) { pc = (unsigned long)&ftrace_call_old; - memcpy(&old, &ftrace_call_old, MCOUNT_INSN_SIZE); new = ftrace_call_replace(pc, (unsigned long)func); - ret = ftrace_modify_code(pc, old, new); + ret = ftrace_modify_code(pc, 0, new, false); } #endif @@ -172,7 +128,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) old = ftrace_nop_replace(rec); new = ftrace_call_replace(ip, adjust_address(rec, addr)); - return ftrace_modify_code(rec->ip, old, new); + return ftrace_modify_code(rec->ip, old, new, true); } int ftrace_make_nop(struct module *mod, @@ -185,7 +141,7 @@ int ftrace_make_nop(struct module *mod, old = ftrace_call_replace(ip, adjust_address(rec, addr)); new = ftrace_nop_replace(rec); - ret = ftrace_modify_code(ip, old, new); + ret = ftrace_modify_code(ip, old, new, true); #ifdef CONFIG_OLD_MCOUNT if (ret == -EINVAL && addr == MCOUNT_ADDR) { @@ -193,7 +149,7 @@ int ftrace_make_nop(struct module *mod, old = ftrace_call_replace(ip, adjust_address(rec, addr)); new = ftrace_nop_replace(rec); - ret = ftrace_modify_code(ip, old, new); + ret = ftrace_modify_code(ip, old, new, true); } #endif @@ -249,12 +205,12 @@ static int __ftrace_modify_caller(unsigned long *callsite, { unsigned long caller_fn = (unsigned long) func; unsigned long pc = (unsigned long) callsite; - unsigned long branch = ftrace_gen_branch(pc, caller_fn, false); + unsigned long branch = arm_gen_branch(pc, caller_fn); unsigned long nop = 0xe1a00000; /* mov r0, r0 */ unsigned long old = enable ? nop : branch; unsigned long new = enable ? branch : nop; - return ftrace_modify_code(pc, old, new); + return ftrace_modify_code(pc, old, new, true); } static int ftrace_modify_graph_caller(bool enable) |