From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-hardening@vger.kernel.org, mark.rutland@arm.com,
catalin.marinas@arm.com, will@kernel.org,
Ard Biesheuvel <ardb@kernel.org>
Subject: [RFC PATCH 7/9] arm64: assembler: add unwind annotations to frame push/pop macros
Date: Wed, 13 Oct 2021 17:22:41 +0200 [thread overview]
Message-ID: <20211013152243.2216899-8-ardb@kernel.org> (raw)
In-Reply-To: <20211013152243.2216899-1-ardb@kernel.org>
In order to ensure that we can unwind from hand rolled assembly
routines, decorate the frame push/pop helper macros that are used by
non-leaf assembler routines with the appropriate annotations.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/include/asm/assembler.h | 26 +++++++++++++++++++-
arch/arm64/include/asm/linkage.h | 16 +++++++++++-
2 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index ceed84ac4005..cebb6c8c489b 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -664,9 +664,10 @@ alternative_endif
* the new value of sp. Add @extra bytes of stack space
* for locals.
*/
- .macro frame_push, regcount:req, extra
+ .macro frame_push, regcount:req, extra=0
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
paciasp
+ .cfi_negate_ra_state
#endif
__frame st, \regcount, \extra
.endm
@@ -681,14 +682,29 @@ alternative_endif
__frame ld
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
autiasp
+ .cfi_negate_ra_state
#endif
.endm
.macro __frame_regs, reg1, reg2, op, num
.if .Lframe_regcount == \num
\op\()r \reg1, [sp, #(\num + 1) * 8]
+ .ifc \op, st
+ .cfi_offset \reg1, -.Lframe_cfa_offset
+ .set .Lframe_cfa_offset, .Lframe_cfa_offset - 8
+ .else
+ .cfi_restore \reg1
+ .endif
.elseif .Lframe_regcount > \num
\op\()p \reg1, \reg2, [sp, #(\num + 1) * 8]
+ .ifc \op, st
+ .cfi_offset \reg1, -.Lframe_cfa_offset
+ .cfi_offset \reg2, -.Lframe_cfa_offset + 8
+ .set .Lframe_cfa_offset, .Lframe_cfa_offset - 16
+ .else
+ .cfi_restore \reg1
+ .cfi_restore \reg2
+ .endif
.endif
.endm
@@ -708,7 +724,12 @@ alternative_endif
.set .Lframe_regcount, \regcount
.set .Lframe_extra, \extra
.set .Lframe_local_offset, ((\regcount + 3) / 2) * 16
+ .set .Lframe_cfa_offset, .Lframe_local_offset + .Lframe_extra
stp x29, x30, [sp, #-.Lframe_local_offset - .Lframe_extra]!
+ .cfi_def_cfa_offset .Lframe_cfa_offset
+ .cfi_offset x29, -.Lframe_cfa_offset
+ .cfi_offset x30, -.Lframe_cfa_offset + 8
+ .set .Lframe_cfa_offset, .Lframe_cfa_offset - 16
mov x29, sp
.endif
@@ -723,6 +744,9 @@ alternative_endif
.error "frame_push/frame_pop may not be nested"
.endif
ldp x29, x30, [sp], #.Lframe_local_offset + .Lframe_extra
+ .cfi_restore x29
+ .cfi_restore x30
+ .cfi_def_cfa_offset 0
.set .Lframe_regcount, -1
.endif
.endm
diff --git a/arch/arm64/include/asm/linkage.h b/arch/arm64/include/asm/linkage.h
index 9906541a6861..d984a6750b01 100644
--- a/arch/arm64/include/asm/linkage.h
+++ b/arch/arm64/include/asm/linkage.h
@@ -4,6 +4,9 @@
#define __ALIGN .align 2
#define __ALIGN_STR ".align 2"
+#define SYM_FUNC_CFI_START .cfi_startproc ;
+#define SYM_FUNC_CFI_END .cfi_endproc ;
+
#if defined(CONFIG_ARM64_BTI_KERNEL) && defined(__aarch64__)
/*
@@ -12,6 +15,9 @@
* instead.
*/
#define BTI_C hint 34 ;
+#else
+#define BTI_C
+#endif
/*
* When using in-kernel BTI we need to ensure that PCS-conformant assembly
@@ -20,29 +26,37 @@
*/
#define SYM_FUNC_START(name) \
SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \
+ SYM_FUNC_CFI_START \
BTI_C
#define SYM_FUNC_START_NOALIGN(name) \
SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \
+ SYM_FUNC_CFI_START \
BTI_C
#define SYM_FUNC_START_LOCAL(name) \
SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \
+ SYM_FUNC_CFI_START \
BTI_C
#define SYM_FUNC_START_LOCAL_NOALIGN(name) \
SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \
+ SYM_FUNC_CFI_START \
BTI_C
#define SYM_FUNC_START_WEAK(name) \
SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \
+ SYM_FUNC_CFI_START \
BTI_C
#define SYM_FUNC_START_WEAK_NOALIGN(name) \
SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \
+ SYM_FUNC_CFI_START \
BTI_C
-#endif
+#define SYM_FUNC_END(name) \
+ SYM_FUNC_CFI_END \
+ SYM_END(name, SYM_T_FUNC)
/*
* Annotate a function as position independent, i.e., safe to be called before
--
2.30.2
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next prev parent reply other threads:[~2021-10-13 15:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-13 15:22 [RFC PATCH 0/9] arm64: use unwind data on GCC for shadow call stack Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 1/9] arm64: assembler: enable PAC for non-leaf assembler routines Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 2/9] arm64: cache: use ALIAS version of linkage macros for local aliases Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 3/9] arm64: crypto: avoid overlapping linkage definitions for AES-CBC Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 4/9] arm64: aes-neonbs: move frame pop to end of function Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 5/9] arm64: chacha-neon: move frame pop forward Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 6/9] arm64: smccc: create proper stack frames for HVC/SMC calls Ard Biesheuvel
2021-10-13 15:44 ` Mark Brown
2021-10-13 15:22 ` Ard Biesheuvel [this message]
2021-10-13 15:22 ` [RFC PATCH 8/9] arm64: unwind: add asynchronous unwind tables to the kernel proper Ard Biesheuvel
2021-10-13 15:22 ` [RFC PATCH 9/9] arm64: implement dynamic shadow call stack for GCC Ard Biesheuvel
2021-10-13 15:42 ` Mark Brown
2021-10-13 22:35 ` Dan Li
2021-10-14 9:41 ` Ard Biesheuvel
2021-10-13 17:52 ` [RFC PATCH 0/9] arm64: use unwind data on GCC for shadow call stack Ard Biesheuvel
2021-10-13 18:01 ` Nick Desaulniers
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