x86/unwind/orc: Add 'signal' field to ORC metadata

Add a 'signal' field which allows unwind hints to specify whether the
instruction pointer should be taken literally (like for most interrupts
and exceptions) rather than decremented (like for call stack return
addresses) when used to find the next ORC entry.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/d2c5ec4d83a45b513d8fd72fab59f1a8cfa46871.1676068346.git.jpoimboe@kernel.org

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dcdaf546cd213e4d0eef389a43ad50..1343a62106de9ec3cca2f86f62b1bfe3d4cbb99b 100644 (file)
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -57,12 +57,14 @@ struct orc_entry {
        unsigned        sp_reg:4;
        unsigned        bp_reg:4;
        unsigned        type:2;
+       unsigned        signal:1;
        unsigned        end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
        unsigned        bp_reg:4;
        unsigned        sp_reg:4;
-       unsigned        unused:5;
+       unsigned        unused:4;
        unsigned        end:1;
+       unsigned        signal:1;
        unsigned        type:2;
 #endif
 } __packed;

diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
index f66fbe6537dd7abac82b6bca5e6258f88a81d4b7..e7c71750b3093d591f79508758db3017ebc872b3 100644 (file)
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -15,7 +15,7 @@
        UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
 .endm
 
-.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
+.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 signal=1
        .if \base == %rsp
                .if \indirect
                        .set sp_reg, ORC_REG_SP_INDIRECT
@@ -45,11 +45,11 @@
                .set type, UNWIND_HINT_TYPE_REGS
        .endif
 
-       UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+       UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type signal=\signal
 .endm
 
-.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
-       UNWIND_HINT_REGS base=\base offset=\offset partial=1
+.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 signal=1
+       UNWIND_HINT_REGS base=\base offset=\offset partial=1 signal=\signal
 .endm
 
 .macro UNWIND_HINT_FUNC
@@ -67,7 +67,7 @@
 #else
 
 #define UNWIND_HINT_FUNC \
-       UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0)
+       UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0, 0)
 
 #endif /* __ASSEMBLY__ */
 

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index cdf6c6060170008d2e2bf18d6ba7d2703776dc29..37307b40f8daffdd78861ba9eb865b31689fd32a 100644 (file)
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -484,6 +484,8 @@ bool unwind_next_frame(struct unwind_state *state)
                goto the_end;
        }
 
+       state->signal = orc->signal;
+
        /* Find the previous frame's stack: */
        switch (orc->sp_reg) {
        case ORC_REG_SP:
@@ -563,7 +565,6 @@ bool unwind_next_frame(struct unwind_state *state)
                state->sp = sp;
                state->regs = NULL;
                state->prev_regs = NULL;
-               state->signal = false;
                break;
 
        case UNWIND_HINT_TYPE_REGS:
@@ -587,7 +588,6 @@ bool unwind_next_frame(struct unwind_state *state)
                state->regs = (struct pt_regs *)sp;
                state->prev_regs = NULL;
                state->full_regs = true;
-               state->signal = true;
                break;
 
        case UNWIND_HINT_TYPE_REGS_PARTIAL:
@@ -604,7 +604,6 @@ bool unwind_next_frame(struct unwind_state *state)
                        state->prev_regs = state->regs;
                state->regs = (void *)sp - IRET_FRAME_OFFSET;
                state->full_regs = false;
-               state->signal = true;
                break;
 
        default:

diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 62c54ffbeeaacc74aa9e52697ab11d7deec92d82..9ac3df3fccf0118412f1139521e5c954f0d890d9 100644 (file)
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -15,6 +15,7 @@ struct unwind_hint {
        s16             sp_offset;
        u8              sp_reg;
        u8              type;
+       u8              signal;
        u8              end;
 };
 #endif
@@ -49,7 +50,7 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)              \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end)      \
        "987: \n\t"                                             \
        ".pushsection .discard.unwind_hints\n\t"                \
        /* struct unwind_hint */                                \
@@ -57,6 +58,7 @@ struct unwind_hint {
        ".short " __stringify(sp_offset) "\n\t"                 \
        ".byte " __stringify(sp_reg) "\n\t"                     \
        ".byte " __stringify(type) "\n\t"                       \
+       ".byte " __stringify(signal) "\n\t"                     \
        ".byte " __stringify(end) "\n\t"                        \
        ".balign 4 \n\t"                                        \
        ".popsection\n\t"
@@ -129,7 +131,7 @@ struct unwind_hint {
  * the debuginfo as necessary.  It will also warn if it sees any
  * inconsistencies.
  */
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .Lunwind_hint_ip_\@:
        .pushsection .discard.unwind_hints
                /* struct unwind_hint */
@@ -137,6 +139,7 @@ struct unwind_hint {
                .short \sp_offset
                .byte \sp_reg
                .byte \type
+               .byte \signal
                .byte \end
                .balign 4
        .popsection
@@ -174,7 +177,7 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)      \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
        "\n\t"
 #define STACK_FRAME_NON_STANDARD(func)
 #define STACK_FRAME_NON_STANDARD_FP(func)
@@ -182,7 +185,7 @@ struct unwind_hint {
 #define ASM_REACHABLE
 #else
 #define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm

diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dcdaf546cd213e4d0eef389a43ad50..1343a62106de9ec3cca2f86f62b1bfe3d4cbb99b 100644 (file)
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -57,12 +57,14 @@ struct orc_entry {
        unsigned        sp_reg:4;
        unsigned        bp_reg:4;
        unsigned        type:2;
+       unsigned        signal:1;
        unsigned        end:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
        unsigned        bp_reg:4;
        unsigned        sp_reg:4;
-       unsigned        unused:5;
+       unsigned        unused:4;
        unsigned        end:1;
+       unsigned        signal:1;
        unsigned        type:2;
 #endif
 } __packed;

diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index 62c54ffbeeaacc74aa9e52697ab11d7deec92d82..9ac3df3fccf0118412f1139521e5c954f0d890d9 100644 (file)
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -15,6 +15,7 @@ struct unwind_hint {
        s16             sp_offset;
        u8              sp_reg;
        u8              type;
+       u8              signal;
        u8              end;
 };
 #endif
@@ -49,7 +50,7 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)              \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end)      \
        "987: \n\t"                                             \
        ".pushsection .discard.unwind_hints\n\t"                \
        /* struct unwind_hint */                                \
@@ -57,6 +58,7 @@ struct unwind_hint {
        ".short " __stringify(sp_offset) "\n\t"                 \
        ".byte " __stringify(sp_reg) "\n\t"                     \
        ".byte " __stringify(type) "\n\t"                       \
+       ".byte " __stringify(signal) "\n\t"                     \
        ".byte " __stringify(end) "\n\t"                        \
        ".balign 4 \n\t"                                        \
        ".popsection\n\t"
@@ -129,7 +131,7 @@ struct unwind_hint {
  * the debuginfo as necessary.  It will also warn if it sees any
  * inconsistencies.
  */
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .Lunwind_hint_ip_\@:
        .pushsection .discard.unwind_hints
                /* struct unwind_hint */
@@ -137,6 +139,7 @@ struct unwind_hint {
                .short \sp_offset
                .byte \sp_reg
                .byte \type
+               .byte \signal
                .byte \end
                .balign 4
        .popsection
@@ -174,7 +177,7 @@ struct unwind_hint {
 
 #ifndef __ASSEMBLY__
 
-#define UNWIND_HINT(sp_reg, sp_offset, type, end)      \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
        "\n\t"
 #define STACK_FRAME_NON_STANDARD(func)
 #define STACK_FRAME_NON_STANDARD_FP(func)
@@ -182,7 +185,7 @@ struct unwind_hint {
 #define ASM_REACHABLE
 #else
 #define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
 .endm
 .macro STACK_FRAME_NON_STANDARD func:req
 .endm

diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 4f1211fec82ce0bb77eb0f4d236ff8e30ddd2e59..2d8ebdcd1db3c18b43d44ff6f97ebaf268d668e5 100644 (file)
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -211,8 +211,8 @@ int orc_dump(const char *_objname)
 
                print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
 
-               printf(" type:%s end:%d\n",
-                      orc_type_name(orc[i].type), orc[i].end);
+               printf(" type:%s signal:%d end:%d\n",
+                      orc_type_name(orc[i].type), orc[i].signal, orc[i].end);
        }
 
        elf_end(elf);