I just went over this when looking at some Xen-related ftrace initialization
problems. They were related to Xen code that is not upstream but this clean up
would make sense here.
I think that this was already the intention when text_ip_addr() was introduced
in the commit 87fbb2ac6073a703930 (ftrace/x86: Use breakpoints for converting
function graph caller). Anyway, better do it now before it shots people into
their leg ;-)
Signed-off-by: Petr Mladek <pmla...@suse.cz>
---
arch/x86/kernel/ftrace.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 89de3eaf8772..cbc4a91b131e 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -297,16 +297,7 @@ 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;
--
1.8.4
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