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Subject[TRIVIAL PATCH 01/26] vsprintf: Add extension %pSR - print_symbol replacement
Date
print_symbol takes a long and converts it to a function
name and offset. %pS does something similar, but doesn't
translate the address via __builtin_extract_return_addr.
%pSR does the translation.

This will enable replacing multiple calls like
printk(...);
printk_symbol(addr);
printk("\n");
with a single non-interleavable in dmesg
printk("... %pSR\n", (void *)addr);

Update documentation too.

Signed-off-by: Joe Perches <joe@perches.com>
---
Documentation/printk-formats.txt | 2 ++
lib/vsprintf.c | 18 +++++++++++++-----
2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 8ffb274..69a5ca1 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -17,6 +17,8 @@ Symbols/Function Pointers:
%pF versatile_init+0x0/0x110
%pf versatile_init
%pS versatile_init+0x0/0x110
+ %pSR versatile_init+0x9/0x110
+ (with __builtin_extract_return_addr() translation)
%ps versatile_init
%pB prev_fn_of_versatile_init+0x88/0x88

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index fab33a9..832ff0b 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -534,14 +534,21 @@ char *string(char *buf, char *end, const char *s, struct printf_spec spec)

static noinline_for_stack
char *symbol_string(char *buf, char *end, void *ptr,
- struct printf_spec spec, char ext)
+ struct printf_spec spec, const char *fmt)
{
- unsigned long value = (unsigned long) ptr;
+ unsigned long value;
#ifdef CONFIG_KALLSYMS
char sym[KSYM_SYMBOL_LEN];
- if (ext == 'B')
+#endif
+
+ if (fmt[1] == 'R')
+ ptr = __builtin_extract_return_addr(ptr);
+ value = (unsigned long)ptr;
+
+#ifdef CONFIG_KALLSYMS
+ if (*fmt == 'B')
sprint_backtrace(sym, value);
- else if (ext != 'f' && ext != 's')
+ else if (*fmt != 'f' && *fmt != 's')
sprint_symbol(sym, value);
else
sprint_symbol_no_offset(sym, value);
@@ -987,6 +994,7 @@ int kptr_restrict __read_mostly;
* - 'f' For simple symbolic function names without offset
* - 'S' For symbolic direct pointers with offset
* - 's' For symbolic direct pointers without offset
+ * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
* - 'B' For backtraced symbolic direct pointers with offset
* - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
* - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
@@ -1059,7 +1067,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
case 'S':
case 's':
case 'B':
- return symbol_string(buf, end, ptr, spec, *fmt);
+ return symbol_string(buf, end, ptr, spec, fmt);
case 'R':
case 'r':
return resource_string(buf, end, ptr, spec, fmt);
--
1.7.8.112.g3fd21


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