From: Marc Zyngier <marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com> Subject: [PATCH v2 04/19] arm64: alternatives: Enforce alignment of struct alt_instr Date: Mon, 11 Dec 2017 14:49:22 +0000 [thread overview] Message-ID: <20171211144937.4537-5-marc.zyngier@arm.com> (raw) In-Reply-To: <20171211144937.4537-1-marc.zyngier@arm.com> We're playing a dangerous game with struct alt_instr, as we produce it using assembly tricks, but parse them using the C structure. We just assume that the respective alignments of the two will be the same. But as we add more fields to this structure, the alignment requirements of the structure may change, and lead to all kind of funky bugs. TO solve this, let's move the definition of struct alt_instr to its own file, and use this to generate the alignment constraint from asm-offsets.c. The various macros are then patched to take the alignment into account. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/include/asm/alternative.h | 13 +++++-------- arch/arm64/include/asm/alternative_types.h | 13 +++++++++++++ arch/arm64/kernel/asm-offsets.c | 4 ++++ 3 files changed, 22 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/include/asm/alternative_types.h diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 4a85c6952a22..395befde7595 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -2,28 +2,24 @@ #ifndef __ASM_ALTERNATIVE_H #define __ASM_ALTERNATIVE_H +#include <asm/asm-offsets.h> #include <asm/cpucaps.h> #include <asm/insn.h> #ifndef __ASSEMBLY__ +#include <asm/alternative_types.h> + #include <linux/init.h> #include <linux/types.h> #include <linux/stddef.h> #include <linux/stringify.h> -struct alt_instr { - s32 orig_offset; /* offset to original instruction */ - s32 alt_offset; /* offset to replacement instruction */ - u16 cpufeature; /* cpufeature bit set for replacement */ - u8 orig_len; /* size of original instruction(s) */ - u8 alt_len; /* size of new instruction(s), <= orig_len */ -}; - void __init apply_alternatives_all(void); void apply_alternatives(void *start, size_t length); #define ALTINSTR_ENTRY(feature) \ + " .align " __stringify(ALTINSTR_ALIGN) "\n" \ " .word 661b - .\n" /* label */ \ " .word 663f - .\n" /* new instruction */ \ " .hword " __stringify(feature) "\n" /* feature bit */ \ @@ -69,6 +65,7 @@ void apply_alternatives(void *start, size_t length); #include <asm/assembler.h> .macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len + .align ALTINSTR_ALIGN .word \orig_offset - . .word \alt_offset - . .hword \feature diff --git a/arch/arm64/include/asm/alternative_types.h b/arch/arm64/include/asm/alternative_types.h new file mode 100644 index 000000000000..26cf76167f2d --- /dev/null +++ b/arch/arm64/include/asm/alternative_types.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_ALTERNATIVE_TYPES_H +#define __ASM_ALTERNATIVE_TYPES_H + +struct alt_instr { + s32 orig_offset; /* offset to original instruction */ + s32 alt_offset; /* offset to replacement instruction */ + u16 cpufeature; /* cpufeature bit set for replacement */ + u8 orig_len; /* size of original instruction(s) */ + u8 alt_len; /* size of new instruction(s), <= orig_len */ +}; + +#endif diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 74b9a26a84b5..652165c8655a 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -25,6 +25,7 @@ #include <linux/dma-mapping.h> #include <linux/kvm_host.h> #include <linux/suspend.h> +#include <asm/alternative_types.h> #include <asm/cpufeature.h> #include <asm/thread_info.h> #include <asm/memory.h> @@ -151,5 +152,8 @@ int main(void) DEFINE(HIBERN_PBE_ADDR, offsetof(struct pbe, address)); DEFINE(HIBERN_PBE_NEXT, offsetof(struct pbe, next)); DEFINE(ARM64_FTR_SYSVAL, offsetof(struct arm64_ftr_reg, sys_val)); + BLANK(); + DEFINE(ALTINSTR_ALIGN, (63 - __builtin_clzl(__alignof__(struct alt_instr)))); + return 0; } -- 2.14.2
WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 04/19] arm64: alternatives: Enforce alignment of struct alt_instr Date: Mon, 11 Dec 2017 14:49:22 +0000 [thread overview] Message-ID: <20171211144937.4537-5-marc.zyngier@arm.com> (raw) In-Reply-To: <20171211144937.4537-1-marc.zyngier@arm.com> We're playing a dangerous game with struct alt_instr, as we produce it using assembly tricks, but parse them using the C structure. We just assume that the respective alignments of the two will be the same. But as we add more fields to this structure, the alignment requirements of the structure may change, and lead to all kind of funky bugs. TO solve this, let's move the definition of struct alt_instr to its own file, and use this to generate the alignment constraint from asm-offsets.c. The various macros are then patched to take the alignment into account. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/include/asm/alternative.h | 13 +++++-------- arch/arm64/include/asm/alternative_types.h | 13 +++++++++++++ arch/arm64/kernel/asm-offsets.c | 4 ++++ 3 files changed, 22 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/include/asm/alternative_types.h diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 4a85c6952a22..395befde7595 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -2,28 +2,24 @@ #ifndef __ASM_ALTERNATIVE_H #define __ASM_ALTERNATIVE_H +#include <asm/asm-offsets.h> #include <asm/cpucaps.h> #include <asm/insn.h> #ifndef __ASSEMBLY__ +#include <asm/alternative_types.h> + #include <linux/init.h> #include <linux/types.h> #include <linux/stddef.h> #include <linux/stringify.h> -struct alt_instr { - s32 orig_offset; /* offset to original instruction */ - s32 alt_offset; /* offset to replacement instruction */ - u16 cpufeature; /* cpufeature bit set for replacement */ - u8 orig_len; /* size of original instruction(s) */ - u8 alt_len; /* size of new instruction(s), <= orig_len */ -}; - void __init apply_alternatives_all(void); void apply_alternatives(void *start, size_t length); #define ALTINSTR_ENTRY(feature) \ + " .align " __stringify(ALTINSTR_ALIGN) "\n" \ " .word 661b - .\n" /* label */ \ " .word 663f - .\n" /* new instruction */ \ " .hword " __stringify(feature) "\n" /* feature bit */ \ @@ -69,6 +65,7 @@ void apply_alternatives(void *start, size_t length); #include <asm/assembler.h> .macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len + .align ALTINSTR_ALIGN .word \orig_offset - . .word \alt_offset - . .hword \feature diff --git a/arch/arm64/include/asm/alternative_types.h b/arch/arm64/include/asm/alternative_types.h new file mode 100644 index 000000000000..26cf76167f2d --- /dev/null +++ b/arch/arm64/include/asm/alternative_types.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_ALTERNATIVE_TYPES_H +#define __ASM_ALTERNATIVE_TYPES_H + +struct alt_instr { + s32 orig_offset; /* offset to original instruction */ + s32 alt_offset; /* offset to replacement instruction */ + u16 cpufeature; /* cpufeature bit set for replacement */ + u8 orig_len; /* size of original instruction(s) */ + u8 alt_len; /* size of new instruction(s), <= orig_len */ +}; + +#endif diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 74b9a26a84b5..652165c8655a 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -25,6 +25,7 @@ #include <linux/dma-mapping.h> #include <linux/kvm_host.h> #include <linux/suspend.h> +#include <asm/alternative_types.h> #include <asm/cpufeature.h> #include <asm/thread_info.h> #include <asm/memory.h> @@ -151,5 +152,8 @@ int main(void) DEFINE(HIBERN_PBE_ADDR, offsetof(struct pbe, address)); DEFINE(HIBERN_PBE_NEXT, offsetof(struct pbe, next)); DEFINE(ARM64_FTR_SYSVAL, offsetof(struct arm64_ftr_reg, sys_val)); + BLANK(); + DEFINE(ALTINSTR_ALIGN, (63 - __builtin_clzl(__alignof__(struct alt_instr)))); + return 0; } -- 2.14.2
next prev parent reply other threads:[~2017-12-11 14:49 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-12-11 14:49 [PATCH v2 00/19] KVM/arm64: Randomise EL2 mappings Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 01/19] arm64: asm-offsets: Avoid clashing DMA definitions Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 15:03 ` Russell King - ARM Linux 2017-12-11 15:03 ` Russell King - ARM Linux 2017-12-11 15:22 ` Marc Zyngier 2017-12-11 15:22 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 02/19] arm64: asm-offsets: Remove unused definitions Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 03/19] arm64: asm-offsets: Remove potential circular dependency Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier [this message] 2017-12-11 14:49 ` [PATCH v2 04/19] arm64: alternatives: Enforce alignment of struct alt_instr Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 05/19] arm64: alternatives: Add dynamic patching feature Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-13 17:53 ` Catalin Marinas 2017-12-13 17:53 ` Catalin Marinas 2017-12-14 12:22 ` Marc Zyngier 2017-12-14 12:22 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 06/19] arm64: insn: Add N immediate encoding Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 07/19] arm64: insn: Add encoder for bitwise operations using litterals Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-12 18:32 ` James Morse 2017-12-12 18:32 ` James Morse 2017-12-12 23:40 ` Peter Maydell 2017-12-12 23:40 ` Peter Maydell 2017-12-13 14:32 ` Marc Zyngier 2017-12-13 14:32 ` Marc Zyngier 2017-12-13 15:45 ` James Morse 2017-12-13 15:45 ` James Morse 2017-12-13 15:52 ` Marc Zyngier 2017-12-13 15:52 ` Marc Zyngier 2017-12-14 8:40 ` Marc Zyngier 2017-12-14 8:40 ` Marc Zyngier 2017-12-12 18:56 ` Peter Maydell 2017-12-12 18:56 ` Peter Maydell 2017-12-11 14:49 ` [PATCH v2 08/19] arm64: KVM: Dynamically patch the kernel/hyp VA mask Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-14 13:17 ` James Morse 2017-12-14 13:17 ` James Morse 2017-12-14 13:27 ` Marc Zyngier 2017-12-14 13:27 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 09/19] arm64: cpufeatures: Drop the ARM64_HYP_OFFSET_LOW feature flag Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 10/19] KVM: arm/arm64: Do not use kern_hyp_va() with kvm_vgic_global_state Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 11/19] KVM: arm/arm64: Demote HYP VA range display to being a debug feature Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 12/19] KVM: arm/arm64: Move ioremap calls to create_hyp_io_mappings Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 13/19] KVM: arm/arm64: Keep GICv2 HYP VAs in kvm_vgic_global_state Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 14/19] KVM: arm/arm64: Move HYP IO VAs to the "idmap" range Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 15/19] arm64; insn: Add encoder for the EXTR instruction Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 16/19] arm64: insn: Allow ADD/SUB (immediate) with LSL #12 Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 17/19] arm64: KVM: Dynamically compute the HYP VA mask Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 18/19] arm64: KVM: Introduce EL2 VA randomisation Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier 2017-12-11 14:49 ` [PATCH v2 19/19] arm64: Update the KVM memory map documentation Marc Zyngier 2017-12-11 14:49 ` Marc Zyngier
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