| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251112160315.2207947-27-alexandre.chartre@oracle.com>
Date: Wed, 12 Nov 2025 17:03:13 +0100
From: Alexandre Chartre <alexandre.chartre@...cle.com>
To: linux-kernel@...r.kernel.org, mingo@...nel.org, jpoimboe@...nel.org,
peterz@...radead.org
Cc: alexandre.chartre@...cle.com
Subject: [PATCH v3 26/28] objtool: Get the destination name of a PV call
Add a function to get the destination name of a PV call. The destination
depends on the content of the pv_ops[] array which can dynamically change
at runtime.
However there are cases where we can speculate on the content of pv_ops[]
and provide the function name corresponding to the call. For example,
when an alternative depends on the X86_FEATURE_XENPV feature then we know
that the corresponding code will be using the Xen pv_ops[] values.
If we can't figure out the exact content of pv_ops[] then provide the
function name from the default pv_ops[] array.
Signed-off-by: Alexandre Chartre <alexandre.chartre@...cle.com>
---
tools/objtool/arch/x86/decode.c | 2 +-
tools/objtool/check.c | 99 ++++++++++++++++++++++---
tools/objtool/include/objtool/check.h | 4 +
tools/objtool/include/objtool/elf.h | 7 ++
tools/objtool/include/objtool/objtool.h | 6 +-
tools/objtool/objtool.c | 27 ++++++-
6 files changed, 129 insertions(+), 16 deletions(-)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index d651d8921ab47..9fef0d94517ca 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -685,7 +685,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
return -1;
}
- objtool_pv_add(file, idx, func);
+ objtool_pv_add(file, idx, func, PV_MODE_DEFAULT);
}
break;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 1aad636a8d630..7978b3feb0cb2 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -538,7 +538,8 @@ static int decode_instructions(struct objtool_file *file)
/*
* Read the pv_ops[] .data table to find the static initialized values.
*/
-static int add_pv_ops(struct objtool_file *file, const char *symname)
+static int add_pv_ops(struct objtool_file *file, const char *symname,
+ enum pv_mode pv_mode)
{
struct symbol *sym, *func;
unsigned long off, end;
@@ -568,7 +569,7 @@ static int add_pv_ops(struct objtool_file *file, const char *symname)
return -1;
}
- if (objtool_pv_add(file, idx, func))
+ if (objtool_pv_add(file, idx, func, pv_mode))
return -1;
off = reloc_offset(reloc) + 1;
@@ -584,24 +585,27 @@ static int add_pv_ops(struct objtool_file *file, const char *symname)
*/
static int init_pv_ops(struct objtool_file *file)
{
- static const char *pv_ops_tables[] = {
- "pv_ops",
- "xen_cpu_ops",
- "xen_irq_ops",
- "xen_mmu_ops",
- NULL,
+ static struct {
+ const char *name;
+ enum pv_mode mode;
+ } pv_ops_tables[] = {
+ { "pv_ops", PV_MODE_DEFAULT },
+ { "xen_cpu_ops", PV_MODE_XENPV },
+ { "xen_irq_ops", PV_MODE_XENPV },
+ { "xen_mmu_ops", PV_MODE_XENPV },
+ { NULL },
};
const char *pv_ops;
struct symbol *sym;
int idx, nr, ret;
- if (!opts.noinstr)
+ if (!opts.noinstr && !opts.disas)
return 0;
file->pv_ops = NULL;
sym = find_symbol_by_name(file->elf, "pv_ops");
- if (!sym)
+ if (!sym || !sym->len)
return 0;
nr = sym->len / sizeof(unsigned long);
@@ -614,8 +618,8 @@ static int init_pv_ops(struct objtool_file *file)
for (idx = 0; idx < nr; idx++)
INIT_LIST_HEAD(&file->pv_ops[idx].targets);
- for (idx = 0; (pv_ops = pv_ops_tables[idx]); idx++) {
- ret = add_pv_ops(file, pv_ops);
+ for (idx = 0; (pv_ops = pv_ops_tables[idx].name); idx++) {
+ ret = add_pv_ops(file, pv_ops, pv_ops_tables[idx].mode);
if (ret)
return ret;
}
@@ -3379,6 +3383,77 @@ static bool pv_call_dest(struct objtool_file *file, struct instruction *insn)
return file->pv_ops[idx].clean;
}
+/*
+ * Return the name of the destination of a PV call.
+ *
+ * The destination depends on the specified pv_mode. If an exact
+ * destination cannot be found then the name shows the position of
+ * the destination in the pv_ops[] array, and it is followed by
+ * the operation name for the default PV mode. For example:
+ * "pv_ops[61] ~ native_set_pte"
+ *
+ * The destination name can be followed by a '*' character if there
+ * is code that can override the pv_ops[] entry.
+ *
+ * The function returns NULL if there is no call and the operation
+ * is a NOP.
+ */
+const char *pv_call_dest_name(struct objtool_file *file,
+ struct instruction *insn,
+ enum pv_mode pv_mode)
+{
+ struct symbol *target_default = NULL;
+ struct symbol *target = NULL;
+ static char pvname[64];
+ const char *note = "";
+ struct reloc *reloc;
+ int idx;
+
+ reloc = insn_reloc(file, insn);
+ if (!reloc || strcmp(reloc->sym->name, "pv_ops"))
+ return NULL;
+
+ idx = (arch_dest_reloc_offset(reloc_addend(reloc)) / sizeof(void *));
+
+ if (file->pv_ops) {
+
+ target_default = file->pv_ops[idx].target_default;
+
+ switch (pv_mode) {
+
+ case PV_MODE_DEFAULT:
+ target = target_default;
+ break;
+
+ case PV_MODE_XENPV:
+ target = file->pv_ops[idx].target_xen;
+ break;
+
+ case PV_MODE_UNKNOWN:
+ break;
+ }
+
+ if (file->pv_ops[idx].target_override > 0)
+ note = " *";
+ }
+
+ if (target) {
+ if (!strcmp(target->name, "nop_func"))
+ return NULL;
+
+ snprintf(pvname, sizeof(pvname), "%s%s", target->name, note);
+
+ } else if (target_default) {
+ snprintf(pvname, sizeof(pvname), "pv_ops[%d] ~ %s%s",
+ idx, target_default->name, note);
+ } else {
+ snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
+ }
+
+ return pvname;
+}
+
+
static inline bool noinstr_call_dest(struct objtool_file *file,
struct instruction *insn,
struct symbol *func)
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index c54dd0aae1f60..e352ed64f9edd 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -138,6 +138,10 @@ static inline struct symbol *insn_call_dest(struct instruction *insn)
return insn->_call_dest;
}
+const char *pv_call_dest_name(struct objtool_file *file,
+ struct instruction *insn,
+ enum pv_mode pv_mode);
+
struct instruction *find_insn(struct objtool_file *file,
struct section *sec, unsigned long offset);
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index df8434d3b7440..1d55f5da16932 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -46,6 +46,12 @@ struct section {
struct reloc *relocs;
};
+enum pv_mode {
+ PV_MODE_UNKNOWN,
+ PV_MODE_DEFAULT,
+ PV_MODE_XENPV,
+};
+
struct symbol {
struct list_head list;
struct rb_node node;
@@ -72,6 +78,7 @@ struct symbol {
u8 ignore : 1;
u8 nocfi : 1;
struct list_head pv_target;
+ enum pv_mode pv_mode;
struct reloc *relocs;
struct section *group_sec;
};
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
index c0dc86a78ff65..cb25bf502f2b2 100644
--- a/tools/objtool/include/objtool/objtool.h
+++ b/tools/objtool/include/objtool/objtool.h
@@ -17,6 +17,9 @@
struct pv_state {
bool clean;
struct list_head targets;
+ struct symbol *target_default;
+ struct symbol *target_xen;
+ int target_override;
};
struct objtool_file {
@@ -41,7 +44,8 @@ struct objtool_file {
struct objtool_file *objtool_open_read(const char *_objname);
-int objtool_pv_add(struct objtool_file *file, int idx, struct symbol *func);
+int objtool_pv_add(struct objtool_file *file, int idx, struct symbol *func,
+ enum pv_mode pv_mode);
int check(struct objtool_file *file);
int orc_dump(const char *objname);
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 5c8b974ad0f9d..95dfef07a530f 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -44,9 +44,10 @@ struct objtool_file *objtool_open_read(const char *filename)
return &file;
}
-int objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
+int objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func,
+ enum pv_mode pv_mode)
{
- if (!opts.noinstr)
+ if (!opts.noinstr && !opts.disas)
return 0;
if (!f->pv_ops) {
@@ -54,6 +55,28 @@ int objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
return -1;
}
+ if (opts.disas) {
+ switch (pv_mode) {
+
+ case PV_MODE_DEFAULT:
+ if (f->pv_ops[idx].target_default)
+ f->pv_ops[idx].target_override++;
+ else
+ f->pv_ops[idx].target_default = func;
+ break;
+
+ case PV_MODE_XENPV:
+ f->pv_ops[idx].target_xen = func;
+ break;
+
+ default:
+ BUG();
+ }
+ }
+
+ if (!opts.noinstr)
+ return 0;
+
/*
* These functions will be patched into native code,
* see paravirt_patch().
--
2.43.5
Powered by blists - more mailing lists