diff options
Diffstat (limited to 'arch/s390/kernel/ftrace.c')
-rw-r--r-- | arch/s390/kernel/ftrace.c | 65 |
1 files changed, 31 insertions, 34 deletions
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 89c0870d5679..1852d46babb1 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -4,8 +4,7 @@ * * Copyright IBM Corp. 2009,2014 * - * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>, - * Martin Schwidefsky <schwidefsky@de.ibm.com> + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> */ #include <linux/moduleloader.h> @@ -61,18 +60,9 @@ asm( #ifdef CONFIG_EXPOLINE asm( " .align 16\n" - "ftrace_shared_hotpatch_trampoline_ex:\n" - " lmg %r0,%r1,2(%r1)\n" - " ex %r0," __stringify(__LC_BR_R1) "(%r0)\n" - " j .\n" - "ftrace_shared_hotpatch_trampoline_ex_end:\n" -); - -asm( - " .align 16\n" "ftrace_shared_hotpatch_trampoline_exrl:\n" " lmg %r0,%r1,2(%r1)\n" - " .insn ril,0xc60000000000,%r0,0f\n" /* exrl */ + " exrl %r0,0f\n" " j .\n" "0: br %r1\n" "ftrace_shared_hotpatch_trampoline_exrl_end:\n" @@ -91,12 +81,8 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end) tend = ftrace_shared_hotpatch_trampoline_br_end; #ifdef CONFIG_EXPOLINE if (!nospec_disable) { - tstart = ftrace_shared_hotpatch_trampoline_ex; - tend = ftrace_shared_hotpatch_trampoline_ex_end; - if (test_facility(35)) { /* exrl */ - tstart = ftrace_shared_hotpatch_trampoline_exrl; - tend = ftrace_shared_hotpatch_trampoline_exrl_end; - } + tstart = ftrace_shared_hotpatch_trampoline_exrl; + tend = ftrace_shared_hotpatch_trampoline_exrl_end; } #endif /* CONFIG_EXPOLINE */ if (end) @@ -194,25 +180,26 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, return 0; } -static void brcl_disable(void *brcl) +static int ftrace_patch_branch_mask(void *addr, u16 expected, bool enable) { - u8 op = 0x04; /* set mask field to zero */ + u16 old; + u8 op; - s390_kernel_write((char *)brcl + 1, &op, sizeof(op)); + if (get_kernel_nofault(old, addr)) + return -EFAULT; + if (old != expected) + return -EINVAL; + /* set mask field to all ones or zeroes */ + op = enable ? 0xf4 : 0x04; + s390_kernel_write((char *)addr + 1, &op, sizeof(op)); + return 0; } int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - brcl_disable((void *)rec->ip); - return 0; -} - -static void brcl_enable(void *brcl) -{ - u8 op = 0xf4; /* set mask field to all ones */ - - s390_kernel_write((char *)brcl + 1, &op, sizeof(op)); + /* Expect brcl 0xf,... */ + return ftrace_patch_branch_mask((void *)rec->ip, 0xc0f4, false); } int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) @@ -223,8 +210,8 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) if (IS_ERR(trampoline)) return PTR_ERR(trampoline); s390_kernel_write(&trampoline->interceptor, &addr, sizeof(addr)); - brcl_enable((void *)rec->ip); - return 0; + /* Expect brcl 0x0,... */ + return ftrace_patch_branch_mask((void *)rec->ip, 0xc004, true); } int ftrace_update_ftrace_func(ftrace_func_t func) @@ -297,14 +284,24 @@ NOKPROBE_SYMBOL(prepare_ftrace_return); */ int ftrace_enable_ftrace_graph_caller(void) { - brcl_disable(ftrace_graph_caller); + int rc; + + /* Expect brc 0xf,... */ + rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false); + if (rc) + return rc; text_poke_sync_lock(); return 0; } int ftrace_disable_ftrace_graph_caller(void) { - brcl_enable(ftrace_graph_caller); + int rc; + + /* Expect brc 0x0,... */ + rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true); + if (rc) + return rc; text_poke_sync_lock(); return 0; } |