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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	clang-built-linux@googlegroups.com,
	Sami Tolvanen <samitolvanen@google.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 4.19 181/252] arm64: fix alternatives with LLVM's integrated assembler
Date: Fri, 14 Feb 2020 11:10:36 -0500
Message-ID: <20200214161147.15842-181-sashal@kernel.org> (raw)
In-Reply-To: <20200214161147.15842-1-sashal@kernel.org>

From: Sami Tolvanen <samitolvanen@google.com>

[ Upstream commit c54f90c2627cc316d365e3073614731e17dbc631 ]

LLVM's integrated assembler fails with the following error when
building KVM:

  <inline asm>:12:6: error: expected absolute expression
   .if kvm_update_va_mask == 0
       ^
  <inline asm>:21:6: error: expected absolute expression
   .if kvm_update_va_mask == 0
       ^
  <inline asm>:24:2: error: unrecognized instruction mnemonic
          NOT_AN_INSTRUCTION
          ^
  LLVM ERROR: Error parsing inline asm

These errors come from ALTERNATIVE_CB and __ALTERNATIVE_CFG,
which test for the existence of the callback parameter in inline
assembly using the following expression:

  " .if " __stringify(cb) " == 0\n"

This works with GNU as, but isn't supported by LLVM. This change
splits __ALTERNATIVE_CFG and ALTINSTR_ENTRY into separate macros
to fix the LLVM build.

Link: https://github.com/ClangBuiltLinux/linux/issues/472
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/include/asm/alternative.h | 32 ++++++++++++++++++----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h
index 4b650ec1d7dd1..887a8512bf10b 100644
--- a/arch/arm64/include/asm/alternative.h
+++ b/arch/arm64/include/asm/alternative.h
@@ -35,13 +35,16 @@ void apply_alternatives_module(void *start, size_t length);
 static inline void apply_alternatives_module(void *start, size_t length) { }
 #endif
 
-#define ALTINSTR_ENTRY(feature,cb)					      \
+#define ALTINSTR_ENTRY(feature)					              \
 	" .word 661b - .\n"				/* label           */ \
-	" .if " __stringify(cb) " == 0\n"				      \
 	" .word 663f - .\n"				/* new instruction */ \
-	" .else\n"							      \
+	" .hword " __stringify(feature) "\n"		/* feature bit     */ \
+	" .byte 662b-661b\n"				/* source len      */ \
+	" .byte 664f-663f\n"				/* replacement len */
+
+#define ALTINSTR_ENTRY_CB(feature, cb)					      \
+	" .word 661b - .\n"				/* label           */ \
 	" .word " __stringify(cb) "- .\n"		/* callback */	      \
-	" .endif\n"							      \
 	" .hword " __stringify(feature) "\n"		/* feature bit     */ \
 	" .byte 662b-661b\n"				/* source len      */ \
 	" .byte 664f-663f\n"				/* replacement len */
@@ -62,15 +65,14 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
  *
  * Alternatives with callbacks do not generate replacement instructions.
  */
-#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled, cb)	\
+#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled)	\
 	".if "__stringify(cfg_enabled)" == 1\n"				\
 	"661:\n\t"							\
 	oldinstr "\n"							\
 	"662:\n"							\
 	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(feature,cb)					\
+	ALTINSTR_ENTRY(feature)						\
 	".popsection\n"							\
-	" .if " __stringify(cb) " == 0\n"				\
 	".pushsection .altinstr_replacement, \"a\"\n"			\
 	"663:\n\t"							\
 	newinstr "\n"							\
@@ -78,17 +80,25 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 	".popsection\n\t"						\
 	".org	. - (664b-663b) + (662b-661b)\n\t"			\
 	".org	. - (662b-661b) + (664b-663b)\n"			\
-	".else\n\t"							\
+	".endif\n"
+
+#define __ALTERNATIVE_CFG_CB(oldinstr, feature, cfg_enabled, cb)	\
+	".if "__stringify(cfg_enabled)" == 1\n"				\
+	"661:\n\t"							\
+	oldinstr "\n"							\
+	"662:\n"							\
+	".pushsection .altinstructions,\"a\"\n"				\
+	ALTINSTR_ENTRY_CB(feature, cb)					\
+	".popsection\n"							\
 	"663:\n\t"							\
 	"664:\n\t"							\
-	".endif\n"							\
 	".endif\n"
 
 #define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...)	\
-	__ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg), 0)
+	__ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg))
 
 #define ALTERNATIVE_CB(oldinstr, cb) \
-	__ALTERNATIVE_CFG(oldinstr, "NOT_AN_INSTRUCTION", ARM64_CB_PATCH, 1, cb)
+	__ALTERNATIVE_CFG_CB(oldinstr, ARM64_CB_PATCH, 1, cb)
 #else
 
 #include <asm/assembler.h>
-- 
2.20.1


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  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200214161147.15842-1-sashal@kernel.org>
2020-02-14 16:07 ` [PATCH AUTOSEL 4.19 004/252] soc: fsl: qe: change return type of cpm_muram_alloc() to s32 Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 028/252] arm64: cpufeature: Fix the type of no FP/SIMD capability Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 032/252] clocksource/drivers/bcm2835_timer: Fix memory leak of timer Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 037/252] scsi: ufs: Fix ufshcd_probe_hba() reture value in case ufshcd_scsi_add_wlus() fails Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 044/252] ARM: 8952/1: Disable kmemleak on XIP kernels Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 081/252] arm64: dts: allwinner: H6: Add PMU mode Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 082/252] arm: dts: allwinner: H3: Add PMU node Sasha Levin
2020-02-14 16:08 ` [PATCH AUTOSEL 4.19 083/252] ARM: dts: at91: Reenable UART TX pull-ups Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 088/252] ARM: dts: imx6: rdu2: Disable WP for USDHC2 and USDHC3 Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 089/252] ARM: dts: imx6: rdu2: Limit USBH1 to Full Speed Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 091/252] PCI: iproc: Apply quirk_paxc_bridge() for module as well as built-in Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 102/252] Revert "tty/serial: atmel: fix out of range clock divider handling" Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 113/252] drm/mediatek: handle events when enabling/disabling crtc Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 118/252] dmaengine: imx-sdma: Fix memory leak Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 125/252] reset: uniphier: Add SCSSI reset control for each channel Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 127/252] clk: sunxi-ng: add mux and pll notifiers for A64 CPU clock Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 129/252] clk: uniphier: Add SCSSI clock gate for each channel Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 137/252] soc: fsl: qe: remove set but not used variable 'mm_gc' Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 139/252] crypto: atmel-sha - fix error handling when setting hmac key Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 140/252] ARM: dts: stm32: Add power-supply for DSI panel on stm32f469-disco Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 143/252] iommu/arm-smmu-v3: Populate VMID field for CMDQ_OP_TLBI_NH_VA Sasha Levin
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 148/252] ARM: dts: at91: sama5d3: fix maximum peripheral clock rates Sasha Levin
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 149/252] ARM: dts: at91: sama5d3: define clock rate range for tcb1 Sasha Levin
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 155/252] ASoC: atmel: fix build error with CONFIG_SND_ATMEL_SOC_DMA=m Sasha Levin
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 165/252] arm64: ptrace: nofpsimd: Fail FP/SIMD regset operations Sasha Levin
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 177/252] iommu/arm-smmu-v3: Use WRITE_ONCE() when changing validity of an STE Sasha Levin
2020-02-14 16:10 ` Sasha Levin [this message]
2020-02-14 16:10 ` [PATCH AUTOSEL 4.19 186/252] ACPI/IORT: Fix 'Number of IDs' handling in iort_id_map() Sasha Levin
2020-02-14 16:11 ` [PATCH AUTOSEL 4.19 218/252] ARM: 8951/1: Fix Kexec compilation issue Sasha Levin

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