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linux_dsm_epyc7002/arch/arm64/include/asm/jump_label.h

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arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 21:17:13 +07:00
/*
* Copyright (C) 2013 Huawei Ltd.
* Author: Jiang Liu <liuj97@gmail.com>
*
* Based on arch/arm/include/asm/jump_label.h
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_JUMP_LABEL_H
#define __ASM_JUMP_LABEL_H
jump_label: Allow asm/jump_label.h to be included in assembly Wrap asm/jump_label.h for all archs with #ifndef __ASSEMBLY__. Since these are kernel only headers, we don't need #ifdef __KERNEL__ so can simplify things a bit. If an architecture wants to use jump labels in assembly, it will still need to define a macro to create the __jump_table entries (see ARCH_STATIC_BRANCH in the powerpc asm/jump_label.h for an example). Signed-off-by: Anton Blanchard <anton@samba.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: catalin.marinas@arm.com Cc: davem@davemloft.net Cc: heiko.carstens@de.ibm.com Cc: jbaron@akamai.com Cc: linux@arm.linux.org.uk Cc: linuxppc-dev@lists.ozlabs.org Cc: liuj97@gmail.com Cc: mgorman@suse.de Cc: mmarek@suse.cz Cc: mpe@ellerman.id.au Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1428551492-21977-1-git-send-email-anton@samba.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-09 10:51:30 +07:00
#ifndef __ASSEMBLY__
arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 21:17:13 +07:00
#include <linux/types.h>
#include <asm/insn.h>
#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE
arm64/kernel: jump_label: Switch to relative references On a randomly chosen distro kernel build for arm64, vmlinux.o shows the following sections, containing jump label entries, and the associated RELA relocation records, respectively: ... [38088] __jump_table PROGBITS 0000000000000000 00e19f30 000000000002ea10 0000000000000000 WA 0 0 8 [38089] .rela__jump_table RELA 0000000000000000 01fd8bb0 000000000008be30 0000000000000018 I 38178 38088 8 ... In other words, we have 190 KB worth of 'struct jump_entry' instances, and 573 KB worth of RELA entries to relocate each entry's code, target and key members. This means the RELA section occupies 10% of the .init segment, and the two sections combined represent 5% of vmlinux's entire memory footprint. So let's switch from 64-bit absolute references to 32-bit relative references for the code and target field, and a 64-bit relative reference for the 'key' field (which may reside in another module or the core kernel, which may be more than 4 GB way on arm64 when running with KASLR enable): this reduces the size of the __jump_table by 33%, and gets rid of the RELA section entirely. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jessica Yu <jeyu@kernel.org> Link: https://lkml.kernel.org/r/20180919065144.25010-4-ard.biesheuvel@linaro.org
2018-09-19 13:51:38 +07:00
static __always_inline bool arch_static_branch(struct static_key *key,
bool branch)
arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 21:17:13 +07:00
{
arm64/kernel: jump_label: Switch to relative references On a randomly chosen distro kernel build for arm64, vmlinux.o shows the following sections, containing jump label entries, and the associated RELA relocation records, respectively: ... [38088] __jump_table PROGBITS 0000000000000000 00e19f30 000000000002ea10 0000000000000000 WA 0 0 8 [38089] .rela__jump_table RELA 0000000000000000 01fd8bb0 000000000008be30 0000000000000018 I 38178 38088 8 ... In other words, we have 190 KB worth of 'struct jump_entry' instances, and 573 KB worth of RELA entries to relocate each entry's code, target and key members. This means the RELA section occupies 10% of the .init segment, and the two sections combined represent 5% of vmlinux's entire memory footprint. So let's switch from 64-bit absolute references to 32-bit relative references for the code and target field, and a 64-bit relative reference for the 'key' field (which may reside in another module or the core kernel, which may be more than 4 GB way on arm64 when running with KASLR enable): this reduces the size of the __jump_table by 33%, and gets rid of the RELA section entirely. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jessica Yu <jeyu@kernel.org> Link: https://lkml.kernel.org/r/20180919065144.25010-4-ard.biesheuvel@linaro.org
2018-09-19 13:51:38 +07:00
asm_volatile_goto(
"1: nop \n\t"
" .pushsection __jump_table, \"aw\" \n\t"
" .align 3 \n\t"
" .long 1b - ., %l[l_yes] - . \n\t"
" .quad %c0 - . \n\t"
" .popsection \n\t"
locking/static_keys: Add a new static_key interface There are various problems and short-comings with the current static_key interface: - static_key_{true,false}() read like a branch depending on the key value, instead of the actual likely/unlikely branch depending on init value. - static_key_{true,false}() are, as stated above, tied to the static_key init values STATIC_KEY_INIT_{TRUE,FALSE}. - we're limited to the 2 (out of 4) possible options that compile to a default NOP because that's what our arch_static_branch() assembly emits. So provide a new static_key interface: DEFINE_STATIC_KEY_TRUE(name); DEFINE_STATIC_KEY_FALSE(name); Which define a key of different types with an initial true/false value. Then allow: static_branch_likely() static_branch_unlikely() to take a key of either type and emit the right instruction for the case. This means adding a second arch_static_branch_jump() assembly helper which emits a JMP per default. In order to determine the right instruction for the right state, encode the branch type in the LSB of jump_entry::key. This is the final step in removing the naming confusion that has led to a stream of avoidable bugs such as: a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()") ... but it also allows new static key combinations that will give us performance enhancements in the subsequent patches. Tested-by: Rabin Vincent <rabin@rab.in> # arm Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> # ppc Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # s390 Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-24 20:09:55 +07:00
: : "i"(&((char *)key)[branch]) : : l_yes);
return false;
l_yes:
return true;
}
arm64/kernel: jump_label: Switch to relative references On a randomly chosen distro kernel build for arm64, vmlinux.o shows the following sections, containing jump label entries, and the associated RELA relocation records, respectively: ... [38088] __jump_table PROGBITS 0000000000000000 00e19f30 000000000002ea10 0000000000000000 WA 0 0 8 [38089] .rela__jump_table RELA 0000000000000000 01fd8bb0 000000000008be30 0000000000000018 I 38178 38088 8 ... In other words, we have 190 KB worth of 'struct jump_entry' instances, and 573 KB worth of RELA entries to relocate each entry's code, target and key members. This means the RELA section occupies 10% of the .init segment, and the two sections combined represent 5% of vmlinux's entire memory footprint. So let's switch from 64-bit absolute references to 32-bit relative references for the code and target field, and a 64-bit relative reference for the 'key' field (which may reside in another module or the core kernel, which may be more than 4 GB way on arm64 when running with KASLR enable): this reduces the size of the __jump_table by 33%, and gets rid of the RELA section entirely. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jessica Yu <jeyu@kernel.org> Link: https://lkml.kernel.org/r/20180919065144.25010-4-ard.biesheuvel@linaro.org
2018-09-19 13:51:38 +07:00
static __always_inline bool arch_static_branch_jump(struct static_key *key,
bool branch)
locking/static_keys: Add a new static_key interface There are various problems and short-comings with the current static_key interface: - static_key_{true,false}() read like a branch depending on the key value, instead of the actual likely/unlikely branch depending on init value. - static_key_{true,false}() are, as stated above, tied to the static_key init values STATIC_KEY_INIT_{TRUE,FALSE}. - we're limited to the 2 (out of 4) possible options that compile to a default NOP because that's what our arch_static_branch() assembly emits. So provide a new static_key interface: DEFINE_STATIC_KEY_TRUE(name); DEFINE_STATIC_KEY_FALSE(name); Which define a key of different types with an initial true/false value. Then allow: static_branch_likely() static_branch_unlikely() to take a key of either type and emit the right instruction for the case. This means adding a second arch_static_branch_jump() assembly helper which emits a JMP per default. In order to determine the right instruction for the right state, encode the branch type in the LSB of jump_entry::key. This is the final step in removing the naming confusion that has led to a stream of avoidable bugs such as: a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()") ... but it also allows new static key combinations that will give us performance enhancements in the subsequent patches. Tested-by: Rabin Vincent <rabin@rab.in> # arm Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> # ppc Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # s390 Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-24 20:09:55 +07:00
{
arm64/kernel: jump_label: Switch to relative references On a randomly chosen distro kernel build for arm64, vmlinux.o shows the following sections, containing jump label entries, and the associated RELA relocation records, respectively: ... [38088] __jump_table PROGBITS 0000000000000000 00e19f30 000000000002ea10 0000000000000000 WA 0 0 8 [38089] .rela__jump_table RELA 0000000000000000 01fd8bb0 000000000008be30 0000000000000018 I 38178 38088 8 ... In other words, we have 190 KB worth of 'struct jump_entry' instances, and 573 KB worth of RELA entries to relocate each entry's code, target and key members. This means the RELA section occupies 10% of the .init segment, and the two sections combined represent 5% of vmlinux's entire memory footprint. So let's switch from 64-bit absolute references to 32-bit relative references for the code and target field, and a 64-bit relative reference for the 'key' field (which may reside in another module or the core kernel, which may be more than 4 GB way on arm64 when running with KASLR enable): this reduces the size of the __jump_table by 33%, and gets rid of the RELA section entirely. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jessica Yu <jeyu@kernel.org> Link: https://lkml.kernel.org/r/20180919065144.25010-4-ard.biesheuvel@linaro.org
2018-09-19 13:51:38 +07:00
asm_volatile_goto(
"1: b %l[l_yes] \n\t"
" .pushsection __jump_table, \"aw\" \n\t"
" .align 3 \n\t"
" .long 1b - ., %l[l_yes] - . \n\t"
" .quad %c0 - . \n\t"
" .popsection \n\t"
locking/static_keys: Add a new static_key interface There are various problems and short-comings with the current static_key interface: - static_key_{true,false}() read like a branch depending on the key value, instead of the actual likely/unlikely branch depending on init value. - static_key_{true,false}() are, as stated above, tied to the static_key init values STATIC_KEY_INIT_{TRUE,FALSE}. - we're limited to the 2 (out of 4) possible options that compile to a default NOP because that's what our arch_static_branch() assembly emits. So provide a new static_key interface: DEFINE_STATIC_KEY_TRUE(name); DEFINE_STATIC_KEY_FALSE(name); Which define a key of different types with an initial true/false value. Then allow: static_branch_likely() static_branch_unlikely() to take a key of either type and emit the right instruction for the case. This means adding a second arch_static_branch_jump() assembly helper which emits a JMP per default. In order to determine the right instruction for the right state, encode the branch type in the LSB of jump_entry::key. This is the final step in removing the naming confusion that has led to a stream of avoidable bugs such as: a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()") ... but it also allows new static key combinations that will give us performance enhancements in the subsequent patches. Tested-by: Rabin Vincent <rabin@rab.in> # arm Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> # ppc Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # s390 Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-24 20:09:55 +07:00
: : "i"(&((char *)key)[branch]) : : l_yes);
arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 21:17:13 +07:00
return false;
l_yes:
return true;
}
jump_label: Allow asm/jump_label.h to be included in assembly Wrap asm/jump_label.h for all archs with #ifndef __ASSEMBLY__. Since these are kernel only headers, we don't need #ifdef __KERNEL__ so can simplify things a bit. If an architecture wants to use jump labels in assembly, it will still need to define a macro to create the __jump_table entries (see ARCH_STATIC_BRANCH in the powerpc asm/jump_label.h for an example). Signed-off-by: Anton Blanchard <anton@samba.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: catalin.marinas@arm.com Cc: davem@davemloft.net Cc: heiko.carstens@de.ibm.com Cc: jbaron@akamai.com Cc: linux@arm.linux.org.uk Cc: linuxppc-dev@lists.ozlabs.org Cc: liuj97@gmail.com Cc: mgorman@suse.de Cc: mmarek@suse.cz Cc: mpe@ellerman.id.au Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1428551492-21977-1-git-send-email-anton@samba.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-09 10:51:30 +07:00
#endif /* __ASSEMBLY__ */
arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 21:17:13 +07:00
#endif /* __ASM_JUMP_LABEL_H */
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