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Diffstat (limited to 'arch/x86/kernel/ftrace.c')
-rw-r--r--arch/x86/kernel/ftrace.c111
1 files changed, 35 insertions, 76 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index e6253195a30..cbc4a91b131 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -297,18 +297,12 @@ int ftrace_int3_handler(struct pt_regs *regs)
static int ftrace_write(unsigned long ip, const char *val, int size)
{
- /*
- * On x86_64, kernel text mappings are mapped read-only with
- * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead
- * of the kernel text mapping to modify the kernel text.
- *
- * For 32bit kernels, these mappings are same and we can use
- * kernel identity mapping to modify code.
- */
- if (within(ip, (unsigned long)_text, (unsigned long)_etext))
- ip = (unsigned long)__va(__pa_symbol(ip));
+ ip = text_ip_addr(ip);
+
+ if (probe_kernel_write((void *)ip, val, size))
+ return -EPERM;
- return probe_kernel_write((void *)ip, val, size);
+ return 0;
}
static int add_break(unsigned long ip, const char *old)
@@ -323,10 +317,7 @@ static int add_break(unsigned long ip, const char *old)
if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
return -EINVAL;
- if (ftrace_write(ip, &brk, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, &brk, 1);
}
static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -349,40 +340,14 @@ static int add_brk_on_nop(struct dyn_ftrace *rec)
return add_break(rec->ip, old);
}
-/*
- * If the record has the FTRACE_FL_REGS set, that means that it
- * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
- * is not not set, then it wants to convert to the normal callback.
- */
-static unsigned long get_ftrace_addr(struct dyn_ftrace *rec)
-{
- if (rec->flags & FTRACE_FL_REGS)
- return (unsigned long)FTRACE_REGS_ADDR;
- else
- return (unsigned long)FTRACE_ADDR;
-}
-
-/*
- * The FTRACE_FL_REGS_EN is set when the record already points to
- * a function that saves all the regs. Basically the '_EN' version
- * represents the current state of the function.
- */
-static unsigned long get_ftrace_old_addr(struct dyn_ftrace *rec)
-{
- if (rec->flags & FTRACE_FL_REGS_EN)
- return (unsigned long)FTRACE_REGS_ADDR;
- else
- return (unsigned long)FTRACE_ADDR;
-}
-
static int add_breakpoints(struct dyn_ftrace *rec, int enable)
{
unsigned long ftrace_addr;
int ret;
- ret = ftrace_test_record(rec, enable);
+ ftrace_addr = ftrace_get_addr_curr(rec);
- ftrace_addr = get_ftrace_addr(rec);
+ ret = ftrace_test_record(rec, enable);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
@@ -392,10 +357,7 @@ static int add_breakpoints(struct dyn_ftrace *rec, int enable)
/* converting nop to call */
return add_brk_on_nop(rec);
- case FTRACE_UPDATE_MODIFY_CALL_REGS:
case FTRACE_UPDATE_MODIFY_CALL:
- ftrace_addr = get_ftrace_old_addr(rec);
- /* fall through */
case FTRACE_UPDATE_MAKE_NOP:
/* converting a call to a nop */
return add_brk_on_call(rec, ftrace_addr);
@@ -425,7 +387,7 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
/* If this does not have a breakpoint, we are done */
if (ins[0] != brk)
- return -1;
+ return 0;
nop = ftrace_nop_replace();
@@ -440,14 +402,14 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
* If not, don't touch the breakpoint, we make just create
* a disaster.
*/
- ftrace_addr = get_ftrace_addr(rec);
+ ftrace_addr = ftrace_get_addr_new(rec);
nop = ftrace_call_replace(ip, ftrace_addr);
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) == 0)
goto update;
/* Check both ftrace_addr and ftrace_old_addr */
- ftrace_addr = get_ftrace_old_addr(rec);
+ ftrace_addr = ftrace_get_addr_curr(rec);
nop = ftrace_call_replace(ip, ftrace_addr);
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
@@ -455,7 +417,7 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
}
update:
- return probe_kernel_write((void *)ip, &nop[0], 1);
+ return ftrace_write(ip, nop, 1);
}
static int add_update_code(unsigned long ip, unsigned const char *new)
@@ -463,9 +425,7 @@ static int add_update_code(unsigned long ip, unsigned const char *new)
/* skip breakpoint */
ip++;
new++;
- if (ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1);
}
static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -493,13 +453,12 @@ static int add_update(struct dyn_ftrace *rec, int enable)
ret = ftrace_test_record(rec, enable);
- ftrace_addr = get_ftrace_addr(rec);
+ ftrace_addr = ftrace_get_addr_new(rec);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
- case FTRACE_UPDATE_MODIFY_CALL_REGS:
case FTRACE_UPDATE_MODIFY_CALL:
case FTRACE_UPDATE_MAKE_CALL:
/* converting nop to call */
@@ -520,10 +479,7 @@ static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)
new = ftrace_call_replace(ip, addr);
- if (ftrace_write(ip, new, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, new, 1);
}
static int finish_update_nop(struct dyn_ftrace *rec)
@@ -533,9 +489,7 @@ static int finish_update_nop(struct dyn_ftrace *rec)
new = ftrace_nop_replace();
- if (ftrace_write(ip, new, 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, 1);
}
static int finish_update(struct dyn_ftrace *rec, int enable)
@@ -545,13 +499,12 @@ static int finish_update(struct dyn_ftrace *rec, int enable)
ret = ftrace_update_record(rec, enable);
- ftrace_addr = get_ftrace_addr(rec);
+ ftrace_addr = ftrace_get_addr_new(rec);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
- case FTRACE_UPDATE_MODIFY_CALL_REGS:
case FTRACE_UPDATE_MODIFY_CALL:
case FTRACE_UPDATE_MAKE_CALL:
/* converting nop to call */
@@ -628,12 +581,18 @@ void ftrace_replace_code(int enable)
return;
remove_breakpoints:
+ pr_warn("Failed on %s (%d):\n", report, count);
ftrace_bug(ret, rec ? rec->ip : 0);
- printk(KERN_WARNING "Failed on %s (%d):\n", report, count);
for_ftrace_rec_iter(iter) {
rec = ftrace_rec_iter_record(iter);
- remove_breakpoint(rec);
+ /*
+ * Breakpoints are handled only when this function is in
+ * progress. The system could not work with them.
+ */
+ if (remove_breakpoint(rec))
+ BUG();
}
+ run_sync();
}
static int
@@ -655,16 +614,19 @@ ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
run_sync();
ret = ftrace_write(ip, new_code, 1);
- if (ret) {
- ret = -EPERM;
- goto out;
- }
- run_sync();
+ /*
+ * The breakpoint is handled only when this function is in progress.
+ * The system could not work if we could not remove it.
+ */
+ BUG_ON(ret);
out:
+ run_sync();
return ret;
fail_update:
- probe_kernel_write((void *)ip, &old_code[0], 1);
+ /* Also here the system could not work with the breakpoint */
+ if (ftrace_write(ip, old_code, 1))
+ BUG();
goto out;
}
@@ -678,11 +640,8 @@ void arch_ftrace_update_code(int command)
atomic_dec(&modifying_ftrace_code);
}
-int __init ftrace_dyn_arch_init(void *data)
+int __init ftrace_dyn_arch_init(void)
{
- /* The return code is retured via data */
- *(unsigned long *)data = 0;
-
return 0;
}
#endif
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-14 23:33:27 +0000