summaryrefslogtreecommitdiffstats
path: root/arch/arm64/include/asm/alternative.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-24 19:02:15 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-24 19:02:15 +0200
commite3d8238d7f5c3f539a29f5ac596cd342d847e099 (patch)
treef545e6064155d0e943dcfbfabb3de60530a8e5de /arch/arm64/include/asm/alternative.h
parentMerge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm (diff)
parentarm64: use private ratelimit state along with show_unhandled_signals (diff)
downloadlinux-e3d8238d7f5c3f539a29f5ac596cd342d847e099.tar.xz
linux-e3d8238d7f5c3f539a29f5ac596cd342d847e099.zip
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas: "Mostly refactoring/clean-up: - CPU ops and PSCI (Power State Coordination Interface) refactoring following the merging of the arm64 ACPI support, together with handling of Trusted (secure) OS instances - Using fixmap for permanent FDT mapping, removing the initial dtb placement requirements (within 512MB from the start of the kernel image). This required moving the FDT self reservation out of the memreserve processing - Idmap (1:1 mapping used for MMU on/off) handling clean-up - Removing flush_cache_all() - not safe on ARM unless the MMU is off. Last stages of CPU power down/up are handled by firmware already - "Alternatives" (run-time code patching) refactoring and support for immediate branch patching, GICv3 CPU interface access - User faults handling clean-up And some fixes: - Fix for VDSO building with broken ELF toolchains - Fix another case of init_mm.pgd usage for user mappings (during ASID roll-over broadcasting) - Fix for FPSIMD reloading after CPU hotplug - Fix for missing syscall trace exit - Workaround for .inst asm bug - Compat fix for switching the user tls tpidr_el0 register" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (42 commits) arm64: use private ratelimit state along with show_unhandled_signals arm64: show unhandled SP/PC alignment faults arm64: vdso: work-around broken ELF toolchains in Makefile arm64: kernel: rename __cpu_suspend to keep it aligned with arm arm64: compat: print compat_sp instead of sp arm64: mm: Fix freeing of the wrong memmap entries with !SPARSEMEM_VMEMMAP arm64: entry: fix context tracking for el0_sp_pc arm64: defconfig: enable memtest arm64: mm: remove reference to tlb.S from comment block arm64: Do not attempt to use init_mm in reset_context() arm64: KVM: Switch vgic save/restore to alternative_insn arm64: alternative: Introduce feature for GICv3 CPU interface arm64: psci: fix !CONFIG_HOTPLUG_CPU build warning arm64: fix bug for reloading FPSIMD state after CPU hotplug. arm64: kernel thread don't need to save fpsimd context. arm64: fix missing syscall trace exit arm64: alternative: Work around .inst assembler bugs arm64: alternative: Merge alternative-asm.h into alternative.h arm64: alternative: Allow immediate branch as alternative instruction arm64: Rework alternate sequence for ARM erratum 845719 ...
Diffstat (limited to 'arch/arm64/include/asm/alternative.h')
-rw-r--r--arch/arm64/include/asm/alternative.h46
1 files changed, 42 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h
index d261f01e2bae..c385a0c4057f 100644
--- a/arch/arm64/include/asm/alternative.h
+++ b/arch/arm64/include/asm/alternative.h
@@ -1,6 +1,8 @@
#ifndef __ASM_ALTERNATIVE_H
#define __ASM_ALTERNATIVE_H
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
@@ -24,7 +26,20 @@ void free_alternatives_memory(void);
" .byte 662b-661b\n" /* source len */ \
" .byte 664f-663f\n" /* replacement len */
-/* alternative assembly primitive: */
+/*
+ * alternative assembly primitive:
+ *
+ * If any of these .org directive fail, it means that insn1 and insn2
+ * don't have the same length. This used to be written as
+ *
+ * .if ((664b-663b) != (662b-661b))
+ * .error "Alternatives instruction length mismatch"
+ * .endif
+ *
+ * but most assemblers die if insn1 or insn2 have a .inst. This should
+ * be fixed in a binutils release posterior to 2.25.51.0.2 (anything
+ * containing commit 4e4d08cf7399b606 or c1baaddf8861).
+ */
#define ALTERNATIVE(oldinstr, newinstr, feature) \
"661:\n\t" \
oldinstr "\n" \
@@ -37,8 +52,31 @@ void free_alternatives_memory(void);
newinstr "\n" \
"664:\n\t" \
".popsection\n\t" \
- ".if ((664b-663b) != (662b-661b))\n\t" \
- " .error \"Alternatives instruction length mismatch\"\n\t"\
- ".endif\n"
+ ".org . - (664b-663b) + (662b-661b)\n\t" \
+ ".org . - (662b-661b) + (664b-663b)\n"
+
+#else
+
+.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
+ .word \orig_offset - .
+ .word \alt_offset - .
+ .hword \feature
+ .byte \orig_len
+ .byte \alt_len
+.endm
+
+.macro alternative_insn insn1 insn2 cap
+661: \insn1
+662: .pushsection .altinstructions, "a"
+ altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
+ .popsection
+ .pushsection .altinstr_replacement, "ax"
+663: \insn2
+664: .popsection
+ .org . - (664b-663b) + (662b-661b)
+ .org . - (662b-661b) + (664b-663b)
+.endm
+
+#endif /* __ASSEMBLY__ */
#endif /* __ASM_ALTERNATIVE_H */