On 01/14/2016 09:47 PM, Konrad Rzeszutek Wilk wrote:
From: Ross Lagerwall <ross.lagerw...@citrix.com>
Add support for handling bug frames contained with xsplice modules. If a
trap occurs search either the kernel bug table or an applied payload's
bug table depending on the instruction pointer.
Signed-off-by: Ross Lagerwall <ross.lagerw...@citrix.com>
snip
Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
index 5abeb28..02cb4a8 100644
--- a/xen/common/xsplice.c
+++ b/xen/common/xsplice.c
@@ -43,7 +43,10 @@ struct payload {
struct list_head applied_list; /* Linked to 'applied_list'. */
struct xsplice_patch_func *funcs; /* The array of functions to patch.
*/
unsigned int nfuncs; /* Nr of functions to patch. */
-
+ size_t core_size; /* Only .text size. */
+ size_t core_text_size; /* Everything else - .data,.rodata,
etc. */
These comments are the wrong way around.
+ struct bug_frame *start_bug_frames[BUGFRAME_NR]; /* .bug.frame patching. */
+ struct bug_frame *stop_bug_frames[BUGFRAME_NR];
char name[XEN_XSPLICE_NAME_SIZE + 1];/* Name of it. */
};
@@ -544,26 +547,27 @@ static void free_payload_data(struct payload *payload)
payload->payload_pages = 0;
}
-static void calc_section(struct xsplice_elf_sec *sec, size_t *core_size)
+static void calc_section(struct xsplice_elf_sec *sec, size_t *size)
{
- size_t align_size = ROUNDUP(*core_size, sec->sec->sh_addralign);
+ size_t align_size = ROUNDUP(*size, sec->sec->sh_addralign);
sec->sec->sh_entsize = align_size;
- *core_size = sec->sec->sh_size + align_size;
+ *size = sec->sec->sh_size + align_size;
}
static int move_payload(struct payload *payload, struct xsplice_elf *elf)
{
uint8_t *buf;
unsigned int i;
- size_t core_size = 0;
+ size_t size = 0;
/* Compute text regions */
for ( i = 0; i < elf->hdr->e_shnum; i++ )
{
if ( (elf->sec[i].sec->sh_flags & (SHF_ALLOC|SHF_EXECINSTR)) ==
(SHF_ALLOC|SHF_EXECINSTR) )
- calc_section(&elf->sec[i], &core_size);
+ calc_section(&elf->sec[i], &size);
}
+ payload->core_text_size = size;
/* Compute rw data */
for ( i = 0; i < elf->hdr->e_shnum; i++ )
@@ -571,7 +575,7 @@ static int move_payload(struct payload *payload, struct
xsplice_elf *elf)
if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
!(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
(elf->sec[i].sec->sh_flags & SHF_WRITE) )
- calc_section(&elf->sec[i], &core_size);
+ calc_section(&elf->sec[i], &size);
}
/* Compute ro data */
@@ -580,16 +584,17 @@ static int move_payload(struct payload *payload, struct
xsplice_elf *elf)
if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
!(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
!(elf->sec[i].sec->sh_flags & SHF_WRITE) )
- calc_section(&elf->sec[i], &core_size);
+ calc_section(&elf->sec[i], &size);
}
+ payload->core_size = size;
- buf = alloc_payload(core_size);
+ buf = alloc_payload(size);
if ( !buf ) {
printk(XENLOG_ERR "%s: Could not allocate memory for module\n",
elf->name);
return -ENOMEM;
}
- memset(buf, 0, core_size);
+ memset(buf, 0, size);
for ( i = 0; i < elf->hdr->e_shnum; i++ )
{
@@ -604,7 +609,7 @@ static int move_payload(struct payload *payload, struct
xsplice_elf *elf)
}
payload->payload_address = buf;
- payload->payload_pages = PFN_UP(core_size);
+ payload->payload_pages = PFN_UP(size);
These renames should be folded into the originating patch (patch 8) or
dropped.
return 0;
}
@@ -647,6 +652,22 @@ static int find_special_sections(struct payload *payload,
if ( f->pad[j] )
return -EINVAL;
}
+ for ( i = 0; i < BUGFRAME_NR; i++ )
+ {
+ char str[14];
+
+ snprintf(str, sizeof str, ".bug_frames.%d", i);
+ sec = xsplice_elf_sec_by_name(elf, str);
+ if ( !sec )
+ continue;
+
+ if ( ( !sec->sec->sh_size ) ||
+ ( sec->sec->sh_size % sizeof (struct bug_frame) ) )
+ return -EINVAL;
+
+ payload->start_bug_frames[i] = (struct bug_frame *)sec->load_addr;
+ payload->stop_bug_frames[i] = (struct bug_frame *)(sec->load_addr +
sec->sec->sh_size);
+ }
return 0;
}
@@ -942,6 +963,72 @@ void do_xsplice(void)
}
}
+
+/*
+ * Functions for handling special sections.
+ */
+struct bug_frame *xsplice_find_bug(const char *eip, int *id)
+{
+ struct payload *data;
+ struct bug_frame *bug;
+ int i;
+
+ /* No locking since this list is only ever changed during apply or revert
+ * context. */
+ list_for_each_entry ( data, &applied_list, applied_list )
+ {
+ for (i = 0; i < 4; i++) {
BUGFRAME_NR
+ if (!data->start_bug_frames[i])
+ continue;
+ if ( !((void *)eip >= data->payload_address &&
+ (void *)eip < (data->payload_address +
data->core_text_size)))
+ continue;
+
+ for ( bug = data->start_bug_frames[i]; bug !=
data->stop_bug_frames[i]; ++bug ) {
+ if ( bug_loc(bug) == eip )
+ {
+ *id = i;
+ return bug;
+ }
+ }
+ }
+ }
+
+ return NULL;
+}
+
--
Ross Lagerwall
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