[PATCH] arm: enable unaligned accesses by default if EFI is configured
Heinrich reports that compiling with LTO & EFI breaks armv7 and arm11* builds. The reason is that LTO (maybe a binutils bug?) replaces the asm version of allow_unaligned() with the __weak definition of the function. As a result EFI code ends up running with unaligned accesses disabled and eventually crashes.
So let's enable unaligned access for those architectures during our start.S routines and avoid the linker issues.
Reported-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- arch/arm/cpu/arm11/Makefile | 4 ---- arch/arm/cpu/arm11/sctlr.S | 25 ------------------------- arch/arm/cpu/arm1136/start.S | 3 +++ arch/arm/cpu/arm1176/start.S | 3 +++ arch/arm/cpu/armv7/Makefile | 1 - arch/arm/cpu/armv7/sctlr.S | 22 ---------------------- arch/arm/cpu/armv7/start.S | 3 +++ include/asm-generic/unaligned.h | 4 ---- lib/efi_loader/efi_device_path.c | 7 ------- lib/efi_loader/efi_setup.c | 12 ------------ 10 files changed, 9 insertions(+), 75 deletions(-) delete mode 100644 arch/arm/cpu/arm11/sctlr.S delete mode 100644 arch/arm/cpu/armv7/sctlr.S
diff --git a/arch/arm/cpu/arm11/Makefile b/arch/arm/cpu/arm11/Makefile index 5dfa01ae8d05..5d721fce12b5 100644 --- a/arch/arm/cpu/arm11/Makefile +++ b/arch/arm/cpu/arm11/Makefile @@ -4,7 +4,3 @@ # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
obj-y = cpu.o - -ifneq ($(CONFIG_SPL_BUILD),y) -obj-$(CONFIG_EFI_LOADER) += sctlr.o -endif diff --git a/arch/arm/cpu/arm11/sctlr.S b/arch/arm/cpu/arm11/sctlr.S deleted file mode 100644 index 74a7fc4a25b6..000000000000 --- a/arch/arm/cpu/arm11/sctlr.S +++ /dev/null @@ -1,25 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/* - * Routines to access the system control register - * - * Copyright (c) 2019 Heinrich Schuchardt - */ - -#include <linux/linkage.h> - -/* - * void allow_unaligned(void) - allow unaligned access - * - * This routine sets the enable unaligned data support flag and clears the - * aligned flag in the system control register. - * After calling this routine unaligned access does no longer leads to a - * data abort or undefined behavior but is handled by the CPU. - * For details see the "ARM Architecture Reference Manual" for ARMv6. - */ -ENTRY(allow_unaligned) - mrc p15, 0, r0, c1, c0, 0 @ load system control register - orr r0, r0, #1 << 22 @ set unaligned data support flag - bic r0, r0, #2 @ clear aligned flag - mcr p15, 0, r0, c1, c0, 0 @ write system control register - bx lr @ return -ENDPROC(allow_unaligned) diff --git a/arch/arm/cpu/arm1136/start.S b/arch/arm/cpu/arm1136/start.S index 4bc27f637366..f2a18d8f3423 100644 --- a/arch/arm/cpu/arm1136/start.S +++ b/arch/arm/cpu/arm1136/start.S @@ -77,7 +77,10 @@ cpu_init_crit: mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER) + /* allow unaligned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (A) Align +#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache mcr p15, 0, r0, c1, c0, 0
diff --git a/arch/arm/cpu/arm1176/start.S b/arch/arm/cpu/arm1176/start.S index 78a9cc173a39..0c80160702ba 100644 --- a/arch/arm/cpu/arm1176/start.S +++ b/arch/arm/cpu/arm1176/start.S @@ -79,7 +79,10 @@ cpu_init_crit: mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER) + /* allow unailgned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (A) Align +#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
/* Prepare to disable the MMU */ diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index 653eef8ad79e..ca50f6e93e10 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -13,7 +13,6 @@ obj-y += syslib.o obj-$(CONFIG_SYS_ARM_MPU) += mpu_v7r.o
ifneq ($(CONFIG_SPL_BUILD),y) -obj-$(CONFIG_EFI_LOADER) += sctlr.o obj-$(CONFIG_ARMV7_NONSEC) += exception_level.o endif
diff --git a/arch/arm/cpu/armv7/sctlr.S b/arch/arm/cpu/armv7/sctlr.S deleted file mode 100644 index bd56e41afe18..000000000000 --- a/arch/arm/cpu/armv7/sctlr.S +++ /dev/null @@ -1,22 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/* - * Routines to access the system control register - * - * Copyright (c) 2018 Heinrich Schuchardt - */ - -#include <linux/linkage.h> - -/* - * void allow_unaligned(void) - allow unaligned access - * - * This routine clears the aligned flag in the system control register. - * After calling this routine unaligned access does no longer lead to a - * data abort but is handled by the CPU. - */ -ENTRY(allow_unaligned) - mrc p15, 0, r0, c1, c0, 0 @ load system control register - bic r0, r0, #2 @ clear aligned flag - mcr p15, 0, r0, c1, c0, 0 @ write system control register - bx lr @ return -ENDPROC(allow_unaligned) diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 7d7aac021e22..abb89efb9ed5 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -197,7 +197,10 @@ ENTRY(cpu_init_cp15) mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002000 @ clear bits 13 (--V-) bic r0, r0, #0x00000007 @ clear bits 2:0 (-CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER) + /* allow unaligned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (--A-) Align +#endif orr r0, r0, #0x00000800 @ set bit 11 (Z---) BTB #if CONFIG_IS_ENABLED(SYS_ICACHE_OFF) bic r0, r0, #0x00001000 @ clear bit 12 (I) I-cache diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h index 3d33a5a063e8..cf032ce1d4cc 100644 --- a/include/asm-generic/unaligned.h +++ b/include/asm-generic/unaligned.h @@ -19,8 +19,4 @@ #else #error invalid endian #endif - -/* Allow unaligned memory access */ -void allow_unaligned(void); - #endif diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index 3b267b713e98..bbaaf626d9cb 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -954,13 +954,6 @@ static void path_to_uefi(void *uefi, const char *src) { u16 *pos = uefi;
- /* - * efi_set_bootdev() calls this routine indirectly before the UEFI - * subsystem is initialized. So we cannot assume unaligned access to be - * enabled. - */ - allow_unaligned(); - while (*src) { s32 code = utf8_get(&src);
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index 58d4e1340233..bd17db61c697 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -17,15 +17,6 @@
efi_status_t efi_obj_list_initialized = OBJ_LIST_NOT_INITIALIZED;
-/* - * Allow unaligned memory access. - * - * This routine is overridden by architectures providing this feature. - */ -void __weak allow_unaligned(void) -{ -} - /** * efi_init_platform_lang() - define supported languages * @@ -191,9 +182,6 @@ int efi_init_early(void) { efi_status_t ret;
- /* Allow unaligned memory access */ - allow_unaligned(); - /* Initialize root node */ ret = efi_root_node_register(); if (ret != EFI_SUCCESS)
On 3/17/23 14:42, Ilias Apalodimas wrote:
Heinrich reports that compiling with LTO & EFI breaks armv7 and arm11* builds. The reason is that LTO (maybe a binutils bug?) replaces the asm version of allow_unaligned() with the __weak definition of the function. As a result EFI code ends up running with unaligned accesses disabled and eventually crashes.
So let's enable unaligned access for those architectures during our start.S routines and avoid the linker issues.
Reported-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com
The problem was originally reported by Tom. My contribution was to track it down to missing enabling of unaligned access due to a linker problem.
Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org
arch/arm/cpu/arm11/Makefile | 4 ---- arch/arm/cpu/arm11/sctlr.S | 25 ------------------------- arch/arm/cpu/arm1136/start.S | 3 +++ arch/arm/cpu/arm1176/start.S | 3 +++ arch/arm/cpu/armv7/Makefile | 1 - arch/arm/cpu/armv7/sctlr.S | 22 ---------------------- arch/arm/cpu/armv7/start.S | 3 +++ include/asm-generic/unaligned.h | 4 ---- lib/efi_loader/efi_device_path.c | 7 ------- lib/efi_loader/efi_setup.c | 12 ------------ 10 files changed, 9 insertions(+), 75 deletions(-) delete mode 100644 arch/arm/cpu/arm11/sctlr.S delete mode 100644 arch/arm/cpu/armv7/sctlr.S
diff --git a/arch/arm/cpu/arm11/Makefile b/arch/arm/cpu/arm11/Makefile index 5dfa01ae8d05..5d721fce12b5 100644 --- a/arch/arm/cpu/arm11/Makefile +++ b/arch/arm/cpu/arm11/Makefile @@ -4,7 +4,3 @@ # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
obj-y = cpu.o
-ifneq ($(CONFIG_SPL_BUILD),y) -obj-$(CONFIG_EFI_LOADER) += sctlr.o -endif diff --git a/arch/arm/cpu/arm11/sctlr.S b/arch/arm/cpu/arm11/sctlr.S deleted file mode 100644 index 74a7fc4a25b6..000000000000 --- a/arch/arm/cpu/arm11/sctlr.S +++ /dev/null @@ -1,25 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/*
- Routines to access the system control register
- Copyright (c) 2019 Heinrich Schuchardt
- */
-#include <linux/linkage.h>
-/*
- void allow_unaligned(void) - allow unaligned access
- This routine sets the enable unaligned data support flag and clears the
- aligned flag in the system control register.
- After calling this routine unaligned access does no longer leads to a
- data abort or undefined behavior but is handled by the CPU.
- For details see the "ARM Architecture Reference Manual" for ARMv6.
- */
-ENTRY(allow_unaligned)
- mrc p15, 0, r0, c1, c0, 0 @ load system control register
- orr r0, r0, #1 << 22 @ set unaligned data support flag
- bic r0, r0, #2 @ clear aligned flag
- mcr p15, 0, r0, c1, c0, 0 @ write system control register
- bx lr @ return
-ENDPROC(allow_unaligned) diff --git a/arch/arm/cpu/arm1136/start.S b/arch/arm/cpu/arm1136/start.S index 4bc27f637366..f2a18d8f3423 100644 --- a/arch/arm/cpu/arm1136/start.S +++ b/arch/arm/cpu/arm1136/start.S @@ -77,7 +77,10 @@ cpu_init_crit: mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unaligned accesses since EFI requires it */
This comment line is only reached without UEFI support. So here you should explain why we forbid unaligned access without UEFI.
Best regards
Heinrich
orr r0, r0, #0x00000002 @ set bit 1 (A) Align +#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache mcr p15, 0, r0, c1, c0, 0
diff --git a/arch/arm/cpu/arm1176/start.S b/arch/arm/cpu/arm1176/start.S index 78a9cc173a39..0c80160702ba 100644 --- a/arch/arm/cpu/arm1176/start.S +++ b/arch/arm/cpu/arm1176/start.S @@ -79,7 +79,10 @@ cpu_init_crit: mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unailgned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (A) Align
+#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
/* Prepare to disable the MMU */ diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index 653eef8ad79e..ca50f6e93e10 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -13,7 +13,6 @@ obj-y += syslib.o obj-$(CONFIG_SYS_ARM_MPU) += mpu_v7r.o
ifneq ($(CONFIG_SPL_BUILD),y) -obj-$(CONFIG_EFI_LOADER) += sctlr.o obj-$(CONFIG_ARMV7_NONSEC) += exception_level.o endif
diff --git a/arch/arm/cpu/armv7/sctlr.S b/arch/arm/cpu/armv7/sctlr.S deleted file mode 100644 index bd56e41afe18..000000000000 --- a/arch/arm/cpu/armv7/sctlr.S +++ /dev/null @@ -1,22 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/*
- Routines to access the system control register
- Copyright (c) 2018 Heinrich Schuchardt
- */
-#include <linux/linkage.h>
-/*
- void allow_unaligned(void) - allow unaligned access
- This routine clears the aligned flag in the system control register.
- After calling this routine unaligned access does no longer lead to a
- data abort but is handled by the CPU.
- */
-ENTRY(allow_unaligned)
- mrc p15, 0, r0, c1, c0, 0 @ load system control register
- bic r0, r0, #2 @ clear aligned flag
- mcr p15, 0, r0, c1, c0, 0 @ write system control register
- bx lr @ return
-ENDPROC(allow_unaligned) diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 7d7aac021e22..abb89efb9ed5 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -197,7 +197,10 @@ ENTRY(cpu_init_cp15) mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002000 @ clear bits 13 (--V-) bic r0, r0, #0x00000007 @ clear bits 2:0 (-CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unaligned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (--A-) Align
+#endif orr r0, r0, #0x00000800 @ set bit 11 (Z---) BTB #if CONFIG_IS_ENABLED(SYS_ICACHE_OFF) bic r0, r0, #0x00001000 @ clear bit 12 (I) I-cache diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h index 3d33a5a063e8..cf032ce1d4cc 100644 --- a/include/asm-generic/unaligned.h +++ b/include/asm-generic/unaligned.h @@ -19,8 +19,4 @@ #else #error invalid endian #endif
-/* Allow unaligned memory access */ -void allow_unaligned(void);
- #endif
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index 3b267b713e98..bbaaf626d9cb 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -954,13 +954,6 @@ static void path_to_uefi(void *uefi, const char *src) { u16 *pos = uefi;
- /*
* efi_set_bootdev() calls this routine indirectly before the UEFI* subsystem is initialized. So we cannot assume unaligned access to be* enabled.*/- allow_unaligned();
- while (*src) { s32 code = utf8_get(&src);
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index 58d4e1340233..bd17db61c697 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -17,15 +17,6 @@
efi_status_t efi_obj_list_initialized = OBJ_LIST_NOT_INITIALIZED;
-/*
- Allow unaligned memory access.
- This routine is overridden by architectures providing this feature.
- */
-void __weak allow_unaligned(void) -{ -}
- /**
- efi_init_platform_lang() - define supported languages
@@ -191,9 +182,6 @@ int efi_init_early(void) { efi_status_t ret;
- /* Allow unaligned memory access */
- allow_unaligned();
- /* Initialize root node */ ret = efi_root_node_register(); if (ret != EFI_SUCCESS)
Hi Heinrich,
On Fri, Mar 17, 2023 at 02:56:02PM +0100, Heinrich Schuchardt wrote:
On 3/17/23 14:42, Ilias Apalodimas wrote:
Heinrich reports that compiling with LTO & EFI breaks armv7 and arm11* builds. The reason is that LTO (maybe a binutils bug?) replaces the asm version of allow_unaligned() with the __weak definition of the function. As a result EFI code ends up running with unaligned accesses disabled and eventually crashes.
So let's enable unaligned access for those architectures during our start.S routines and avoid the linker issues.
Reported-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com
The problem was originally reported by Tom. My contribution was to track it down to missing enabling of unaligned access due to a linker problem.
Ah thanks, I'll fix that in v2
[...]
bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unaligned accesses since EFI requires it */
This comment line is only reached without UEFI support. So here you should explain why we forbid unaligned access without UEFI.
I am not sure I am following. I don't really remember why we had UA disabled on armv7. Do you have any suggestions?
regards /Ilias
Best regards
Heinrich
orr r0, r0, #0x00000002 @ set bit 1 (A) Align +#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache mcr p15, 0, r0, c1, c0, 0 diff --git a/arch/arm/cpu/arm1176/start.S b/arch/arm/cpu/arm1176/start.S index 78a9cc173a39..0c80160702ba 100644 --- a/arch/arm/cpu/arm1176/start.S +++ b/arch/arm/cpu/arm1176/start.S @@ -79,7 +79,10 @@ cpu_init_crit: mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unailgned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (A) Align
+#endif orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache /* Prepare to disable the MMU */ diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index 653eef8ad79e..ca50f6e93e10 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -13,7 +13,6 @@ obj-y += syslib.o obj-$(CONFIG_SYS_ARM_MPU) += mpu_v7r.o ifneq ($(CONFIG_SPL_BUILD),y) -obj-$(CONFIG_EFI_LOADER) += sctlr.o obj-$(CONFIG_ARMV7_NONSEC) += exception_level.o endif diff --git a/arch/arm/cpu/armv7/sctlr.S b/arch/arm/cpu/armv7/sctlr.S deleted file mode 100644 index bd56e41afe18..000000000000 --- a/arch/arm/cpu/armv7/sctlr.S +++ /dev/null @@ -1,22 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/*
- Routines to access the system control register
- Copyright (c) 2018 Heinrich Schuchardt
- */
-#include <linux/linkage.h>
-/*
- void allow_unaligned(void) - allow unaligned access
- This routine clears the aligned flag in the system control register.
- After calling this routine unaligned access does no longer lead to a
- data abort but is handled by the CPU.
- */
-ENTRY(allow_unaligned)
- mrc p15, 0, r0, c1, c0, 0 @ load system control register
- bic r0, r0, #2 @ clear aligned flag
- mcr p15, 0, r0, c1, c0, 0 @ write system control register
- bx lr @ return
-ENDPROC(allow_unaligned) diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 7d7aac021e22..abb89efb9ed5 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -197,7 +197,10 @@ ENTRY(cpu_init_cp15) mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002000 @ clear bits 13 (--V-) bic r0, r0, #0x00000007 @ clear bits 2:0 (-CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unaligned accesses since EFI requires it */ orr r0, r0, #0x00000002 @ set bit 1 (--A-) Align
+#endif orr r0, r0, #0x00000800 @ set bit 11 (Z---) BTB #if CONFIG_IS_ENABLED(SYS_ICACHE_OFF) bic r0, r0, #0x00001000 @ clear bit 12 (I) I-cache diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h index 3d33a5a063e8..cf032ce1d4cc 100644 --- a/include/asm-generic/unaligned.h +++ b/include/asm-generic/unaligned.h @@ -19,8 +19,4 @@ #else #error invalid endian #endif
-/* Allow unaligned memory access */ -void allow_unaligned(void);
- #endif
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index 3b267b713e98..bbaaf626d9cb 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -954,13 +954,6 @@ static void path_to_uefi(void *uefi, const char *src) { u16 *pos = uefi;
- /*
* efi_set_bootdev() calls this routine indirectly before the UEFI* subsystem is initialized. So we cannot assume unaligned access to be* enabled.*/- allow_unaligned();
- while (*src) { s32 code = utf8_get(&src);
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index 58d4e1340233..bd17db61c697 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -17,15 +17,6 @@ efi_status_t efi_obj_list_initialized = OBJ_LIST_NOT_INITIALIZED; -/*
- Allow unaligned memory access.
- This routine is overridden by architectures providing this feature.
- */
-void __weak allow_unaligned(void) -{ -}
- /**
- efi_init_platform_lang() - define supported languages
@@ -191,9 +182,6 @@ int efi_init_early(void) { efi_status_t ret;
- /* Allow unaligned memory access */
- allow_unaligned();
- /* Initialize root node */ ret = efi_root_node_register(); if (ret != EFI_SUCCESS)
On Fri, Mar 17, 2023 at 04:01:58PM +0200, Ilias Apalodimas wrote:
Hi Heinrich,
On Fri, Mar 17, 2023 at 02:56:02PM +0100, Heinrich Schuchardt wrote:
On 3/17/23 14:42, Ilias Apalodimas wrote:
Heinrich reports that compiling with LTO & EFI breaks armv7 and arm11* builds. The reason is that LTO (maybe a binutils bug?) replaces the asm version of allow_unaligned() with the __weak definition of the function. As a result EFI code ends up running with unaligned accesses disabled and eventually crashes.
So let's enable unaligned access for those architectures during our start.S routines and avoid the linker issues.
Reported-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com
The problem was originally reported by Tom. My contribution was to track it down to missing enabling of unaligned access due to a linker problem.
Ah thanks, I'll fix that in v2
[...]
bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) +#if !CONFIG_IS_ENABLED(EFI_LOADER)
- /* allow unaligned accesses since EFI requires it */
This comment line is only reached without UEFI support. So here you should explain why we forbid unaligned access without UEFI.
I am not sure I am following. I don't really remember why we had UA disabled on armv7. Do you have any suggestions?
Poke around git blame here, there should be enough links to bring up what / why we do what we do :)
participants (3)
-
Heinrich Schuchardt -
Ilias Apalodimas -
Tom Rini