print_vma_addr is another function to emit useful
data similar to print_symbol. The print_symbol
functionality has been added via %p[fFsS] vsprintf
extensions.
Perhaps it's appropriate to add vma_addr address
decoding to vsprintf too.
This would allow code conversions where the very
unlikely interleaving of messages from multiple
threads might occur.
like arch/x86/kernel/traps.c:
from:
if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
printk_ratelimit()) {
pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
tsk->comm, tsk->pid, str,
regs->ip, regs->sp, error_code);
print_vma_addr(" in ", regs->ip);
pr_cont("\n");
to:
pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx in %pav\n",
regs->ip, regs->sp, error_code, ®s->ip);
}
Something like:
---
Documentation/printk-formats.txt | 5 ++++
lib/vsprintf.c | 62 ++++++++++++++++++++++++++++++++++++----
2 files changed, 61 insertions(+), 6 deletions(-)
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 2ec6d84..962f82c 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -86,6 +86,11 @@ DMA addresses types dma_addr_t:
For printing a dma_addr_t type which can vary based on build options,
regardless of the width of the CPU data path. Passed by reference.
+VMA addresses: where the content of an unsigned long * is used in find_vma()
+ %pav "%s[%lx+%lx]",
+ kbasename(d_path(vma->vm_file)),
+ vma->vm_start, vma->vm_end - vma->vm_start)
+
Raw buffer as an escaped string:
%*pE[achnops]
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 8243e2f..f4956c1 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1313,23 +1313,70 @@ char *netdev_feature_string(char *buf, char *end, const
u8 *addr,
}
static noinline_for_stack
+char *vma_addr(char *buf, char *end, const void *addr,
+ struct printf_spec spec, const char *fmt)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long ip = *(unsigned long *)addr;
+ char *rtn;
+
+ /* if we are in atomic contexts (in exception stacks, etc.) */
+ if (preempt_count())
+ return string(buf, end, "(atomic context)", spec);
+
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, ip);
+ if (vma && vma->vm_file) {
+ struct file *f = vma->vm_file;
+ char *gfp_buf = (char *)__get_free_page(GFP_KERNEL);
+
+ if (gfp_buf) {
+ char *p = d_path(&f->f_path, gfp_buf, PAGE_SIZE);
+
+ if (IS_ERR(p))
+ p = "?";
+
+ rtn = buf + snprintf(buf, end > buf ? end - buf : 0,
+ "%s[%lx+%lx]",
+ kbasename(p),
+ vma->vm_start,
+ vma->vm_end - vma->vm_start);
+
+ free_page((unsigned long)gfp_buf);
+ } else {
+ rtn = string(buf, end, "(__get_free_page failed)",
spec);
+ }
+ } else {
+ rtn = string(buf, end, "(find_vma failed)", spec);
+ }
+
+ up_read(&mm->mmap_sem);
+
+ return rtn;
+}
+
+static noinline_for_stack
char *address_val(char *buf, char *end, const void *addr,
struct printf_spec spec, const char *fmt)
{
unsigned long long num;
- spec.flags |= SPECIAL | SMALL | ZEROPAD;
- spec.base = 16;
-
switch (fmt[1]) {
+ case 'v':
+ return vma_addr(buf, end, addr, spec, fmt);
case 'd':
- num = *(const dma_addr_t *)addr;
+ spec.flags |= SPECIAL | SMALL | ZEROPAD;
+ spec.base = 16;
spec.field_width = sizeof(dma_addr_t) * 2 + 2;
+ num = *(const dma_addr_t *)addr;
break;
case 'p':
default:
- num = *(const phys_addr_t *)addr;
+ spec.flags |= SPECIAL | SMALL | ZEROPAD;
+ spec.base = 16;
spec.field_width = sizeof(phys_addr_t) * 2 + 2;
+ num = *(const phys_addr_t *)addr;
break;
}
@@ -1453,7 +1500,10 @@ int kptr_restrict __read_mostly;
* N no separator
* The maximum supported length is 64 bytes of the input. Consider
* to use print_hex_dump() for the larger input.
- * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
+ * - 'a[pdv]' For address types:
+ * [p] phys_addr_t and derivatives (resource_size_t)
+ * [d] dma_addr_t
+ * [v] vma_addr
* (default assumed to be phys_addr_t, passed by reference)
* - 'd[234]' For a dentry name (optionally 2-4 last components)
* - 'D[234]' Same as 'd' but for a struct file
--
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