diff options
Diffstat (limited to 'arch/s390/kernel/ftrace.c')
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 79 |
1 files changed, 2 insertions, 77 deletions
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index fcb009d3edd..f0072125926 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -21,9 +21,8 @@ void mcount_replace_code(void); void ftrace_disable_code(void); void ftrace_enable_insn(void); -#ifdef CONFIG_64BIT /* - * The 64-bit mcount code looks like this: + * The mcount code looks like this: * stg %r14,8(%r15) # offset 0 * larl %r1,<&counter> # offset 6 * brasl %r14,_mcount # offset 12 @@ -34,7 +33,7 @@ void ftrace_enable_insn(void); * Note: we do not patch the first instruction to an unconditional branch, * since that would break kprobes/jprobes. It is easier to leave the larl * instruction in and only modify the second instruction. - * The 64-bit enabled ftrace code block looks like this: + * The enabled ftrace code block looks like this: * larl %r0,.+24 # offset 0 * > lg %r1,__LC_FTRACE_FUNC # offset 6 * br %r1 # offset 12 @@ -71,65 +70,15 @@ asm( #define MCOUNT_INSN_OFFSET 6 #define FTRACE_INSN_SIZE 6 -#else /* CONFIG_64BIT */ -/* - * The 31-bit mcount code looks like this: - * st %r14,4(%r15) # offset 0 - * > bras %r1,0f # offset 4 - * > .long _mcount # offset 8 - * > .long <&counter> # offset 12 - * > 0: l %r14,0(%r1) # offset 16 - * > l %r1,4(%r1) # offset 20 - * basr %r14,%r14 # offset 24 - * l %r14,4(%r15) # offset 26 - * Total length is 30 bytes. The twenty bytes starting from offset 4 - * to offset 24 get overwritten by ftrace_make_nop / ftrace_make_call. - * The 31-bit enabled ftrace code block looks like this: - * st %r14,4(%r15) # offset 0 - * > l %r14,__LC_FTRACE_FUNC # offset 4 - * > j 0f # offset 8 - * > .fill 12,1,0x07 # offset 12 - * 0: basr %r14,%r14 # offset 24 - * l %r14,4(%r14) # offset 26 - * The return points of the mcount/ftrace function have the same offset 26. - * The 31-bit disabled ftrace code block looks like this: - * st %r14,4(%r15) # offset 0 - * > j .+26 # offset 4 - * > j 0f # offset 8 - * > .fill 12,1,0x07 # offset 12 - * 0: basr %r14,%r14 # offset 24 - * l %r14,4(%r14) # offset 26 - * The j instruction branches to offset 30 to skip as many instructions - * as possible. - */ -asm( - " .align 4\n" - "ftrace_disable_code:\n" - " j 1f\n" - " j 0f\n" - " .fill 12,1,0x07\n" - "0: basr %r14,%r14\n" - "1:\n" - " .align 4\n" - "ftrace_enable_insn:\n" - " l %r14,"__stringify(__LC_FTRACE_FUNC)"\n"); - -#define FTRACE_INSN_SIZE 4 - -#endif /* CONFIG_64BIT */ - -#ifdef CONFIG_64BIT int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { return 0; } -#endif int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { -#ifdef CONFIG_64BIT /* Initial replacement of the whole mcount block */ if (addr == MCOUNT_ADDR) { if (probe_kernel_write((void *) rec->ip - MCOUNT_INSN_OFFSET, @@ -138,7 +87,6 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return -EPERM; return 0; } -#endif if (probe_kernel_write((void *) rec->ip, ftrace_disable_code, MCOUNT_INSN_SIZE)) return -EPERM; @@ -196,8 +144,6 @@ out: * the original offset to prepare_ftrace_return and put it back. */ -#ifdef CONFIG_64BIT - int ftrace_enable_ftrace_graph_caller(void) { static unsigned short offset = 0x0002; @@ -216,25 +162,4 @@ int ftrace_disable_ftrace_graph_caller(void) &offset, sizeof(offset)); } -#else /* CONFIG_64BIT */ - -int ftrace_enable_ftrace_graph_caller(void) -{ - unsigned short offset; - - offset = ((void *) prepare_ftrace_return - - (void *) ftrace_graph_caller) / 2; - return probe_kernel_write((void *) ftrace_graph_caller + 2, - &offset, sizeof(offset)); -} - -int ftrace_disable_ftrace_graph_caller(void) -{ - static unsigned short offset = 0x0002; - - return probe_kernel_write((void *) ftrace_graph_caller + 2, - &offset, sizeof(offset)); -} - -#endif /* CONFIG_64BIT */ #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |