kernel.git/arch/arm64/include/asm/alternative.h, branch linux-4.9.y

arm64: alternative: fix build with clang integrated assembler

2020-04-02T15:20:40Z

commit 6f5459da2b8736720afdbd67c4bd2d1edba7d0e3 upstream. Building an arm64 defconfig with clang's integrated assembler, this error occurs: :2:2: error: unrecognized instruction mnemonic _ASM_EXTABLE 9999b, 9f ^ arch/arm64/mm/cache.S:50:1: note: while in macro instantiation user_alt 9f, "dc cvau, x4", "dc civac, x4", 0 ^ While GNU as seems fine with case-sensitive macro instantiations, clang doesn't, so use the actual macro name (_asm_extable) as in the rest of the file. Also checked that the generated assembly matches the GCC output. Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Fixes: 290622efc76e ("arm64: fix "dc cvau" cache operation on errata-affected core") Link: https://github.com/ClangBuiltLinux/linux/issues/924 Signed-off-by: Ilie Halip Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: fix alternatives with LLVM's integrated assembler

2020-02-28T14:42:35Z

[ Upstream commit c54f90c2627cc316d365e3073614731e17dbc631 ] LLVM's integrated assembler fails with the following error when building KVM: :12:6: error: expected absolute expression .if kvm_update_va_mask == 0 ^ :21:6: error: expected absolute expression .if kvm_update_va_mask == 0 ^ :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 Tested-by: Nick Desaulniers Reviewed-by: Kees Cook Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: alternatives: Add dynamic patching feature

2018-07-22T12:27:40Z

Commit dea5e2a4c5bcf196f879a66cebdcca07793e8ba4 upstream. We've so far relied on a patching infrastructure that only gave us a single alternative, without any way to provide a range of potential replacement instructions. For a single feature, this is an all or nothing thing. It would be interesting to have a more flexible grained way of patching the kernel though, where we could dynamically tune the code that gets injected. In order to achive this, let's introduce a new form of dynamic patching, assiciating a callback to a patching site. This callback gets source and target locations of the patching request, as well as the number of instructions to be patched. Dynamic patching is declared with the new ALTERNATIVE_CB and alternative_cb directives: asm volatile(ALTERNATIVE_CB("mov %0, #0\n", callback) : "r" (v)); or alternative_cb callback mov x0, #0 alternative_cb_end where callback is the C function computing the alternative. Reviewed-by: Christoffer Dall Reviewed-by: Catalin Marinas Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

arm64: alternatives: use tpidr_el2 on VHE hosts

2018-07-22T12:27:40Z

Commit 6d99b68933fbcf51f84fcbba49246ce1209ec193 upstream. Now that KVM uses tpidr_el2 in the same way as Linux's cpu_offset in tpidr_el1, merge the two. This saves KVM from save/restoring tpidr_el1 on VHE hosts, and allows future code to blindly access per-cpu variables without triggering world-switch. Signed-off-by: James Morse Reviewed-by: Christoffer Dall Reviewed-by: Catalin Marinas Signed-off-by: Catalin Marinas Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

arm64: Fix circular include of asm/lse.h through linux/jump_label.h

2016-11-05T20:59:06Z

Commit efd9e03facd0 ("arm64: Use static keys for CPU features") introduced support for static keys in asm/cpufeature.h, including linux/jump_label.h. When CC_HAVE_ASM_GOTO is not defined, this causes a circular dependency via linux/atomic.h, asm/lse.h and asm/cpufeature.h. This patch moves the capability macros out out of asm/cpufeature.h into a separate asm/cpucaps.h and modifies some of the #includes accordingly. Fixes: efd9e03facd0 ("arm64: Use static keys for CPU features") Reported-by: Artem Savkov Tested-by: Artem Savkov Signed-off-by: Catalin Marinas Signed-off-by: Will Deacon

treewide: remove redundant #include

2016-10-11T22:06:33Z

Kernel source files need not include explicitly because the top Makefile forces to include it with: -include $(srctree)/include/linux/kconfig.h This commit removes explicit includes except the following: * arch/s390/include/asm/facilities_src.h * tools/testing/radix-tree/linux/kernel.h These two are used for host programs. Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arm64: alternative: add auto-nop infrastructure

2016-09-12T09:45:34Z

In some cases, one side of an alternative sequence is simply a number of NOPs used to balance the other side. Keeping track of this manually is tedious, and the presence of large chains of NOPs makes the code more painful to read than necessary. To ameliorate matters, this patch adds a new alternative_else_nop_endif, which automatically balances an alternative sequence with a trivial NOP sled. In many cases, we would like a NOP-sled in the default case, and instructions patched in in the presence of a feature. To enable the NOPs to be generated automatically for this case, this patch also adds a new alternative_if, and updates alternative_else and alternative_endif to work with either alternative_if or alternative_endif. Cc: Andre Przywara Cc: Catalin Marinas Cc: Dave Martin Cc: James Morse Signed-off-by: Mark Rutland [will: use new nops macro to generate nop sequences] Signed-off-by: Will Deacon

arm64: fix "dc cvau" cache operation on errata-affected core

2016-07-01T10:26:20Z

The ARM errata 819472, 826319, 827319 and 824069 for affected Cortex-A53 cores demand to promote "dc cvau" instructions to "dc civac" as well. Attribute the usage of the instruction in __flush_cache_user_range to also be covered by our alternative patching efforts. For that we introduce an assembly macro which both deals with alternatives while still tagging the instructions as USER. Signed-off-by: Andre Przywara Signed-off-by: Catalin Marinas

Revert "arm64: alternatives: add enable parameter to conditional asm macros"

2016-07-01T10:26:15Z

Commit 77ee306c0aea9 ("arm64: alternatives: add enable parameter to conditional asm macros") extended the alternative assembly macros. Unfortunately this does not really work as one would expect, as the enable parameter in fact correctly protects the alternative section magic, but not the actual code sequences. This results in having both the original instruction(s) _and_ the alternative ones, if enable if false. Since there is no user of this macros anyway, just revert it. This reverts commit 77ee306c0aea9a219daec256ad25982944affef8. Signed-off-by: Andre Przywara Signed-off-by: Catalin Marinas

arm64: switch to relative exception tables

2016-02-24T14:57:26Z

Instead of using absolute addresses for both the exception location and the fixup, use offsets relative to the exception table entry values. Not only does this cut the size of the exception table in half, it is also a prerequisite for KASLR, since absolute exception table entries are subject to dynamic relocation, which is incompatible with the sorting of the exception table that occurs at build time. This patch also introduces the _ASM_EXTABLE preprocessor macro (which exists on x86 as well) and its _asm_extable assembly counterpart, as shorthands to emit exception table entries. Acked-by: Will Deacon Signed-off-by: Ard Biesheuvel Signed-off-by: Catalin Marinas