@@ -48,6 +48,8 @@ cpucap_is_possible(const unsigned int cap)
return IS_ENABLED(CONFIG_ARM64_ERRATUM_843419);
case ARM64_WORKAROUND_1742098:
return IS_ENABLED(CONFIG_ARM64_ERRATUM_1742098);
+ case ARM64_WORKAROUND_2645198:
+ return IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198);
case ARM64_WORKAROUND_2658417:
return IS_ENABLED(CONFIG_ARM64_ERRATUM_2658417);
}
@@ -555,8 +555,7 @@ bool __init arch_hugetlb_valid_size(unsigned long size)
pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
{
- if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) &&
- cpus_have_const_cap(ARM64_WORKAROUND_2645198)) {
+ if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) {
/*
* Break-before-make (BBM) is required for all user space mappings
* when the permission changes from executable to non-executable
@@ -1469,8 +1469,7 @@ early_initcall(prevent_bootmem_remove_init);
pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
{
- if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) &&
- cpus_have_const_cap(ARM64_WORKAROUND_2645198)) {
+ if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) {
/*
* Break-before-make (BBM) is required for all user space mappings
* when the permission changes from executable to non-executable
We use cpus_have_const_cap() to check for ARM64_WORKAROUND_2645198 but this is not necessary and alternative_has_cap() would be preferable. For historical reasons, cpus_have_const_cap() is more complicated than it needs to be. Before cpucaps are finalized, it will perform a bitmap test of the system_cpucaps bitmap, and once cpucaps are finalized it will use an alternative branch. This used to be necessary to handle some race conditions in the window between cpucap detection and the subsequent patching of alternatives and static branches, where different branches could be out-of-sync with one another (or w.r.t. alternative sequences). Now that we use alternative branches instead of static branches, these are all patched atomically w.r.t. one another, and there are only a handful of cases that need special care in the window between cpucap detection and alternative patching. Due to the above, it would be nice to remove cpus_have_const_cap(), and migrate callers over to alternative_has_cap_*(), cpus_have_final_cap(), or cpus_have_cap() depending on when their requirements. This will remove redundant instructions and improve code generation, and will make it easier to determine how each callsite will behave before, during, and after alternative patching. The ARM64_WORKAROUND_2645198 cpucap is detected and patched before any userspace translation table exist, and the workaround is only necessary when manipulating usrspace translation tables which are in use. Thus it is not necessary to use cpus_have_const_cap(), and alternative_has_cap() is equivalent. This patch replaces the use of cpus_have_const_cap() with alternative_has_cap_unlikely(), which will avoid generating code to test the system_cpucaps bitmap and should be better for all subsequent calls at runtime. The ARM64_WORKAROUND_2645198 cpucap is added to cpucap_is_possible() so that code can be elided entirely when this is not possible, and redundant IS_ENABLED() checks are removed. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/cpucaps.h | 2 ++ arch/arm64/mm/hugetlbpage.c | 3 +-- arch/arm64/mm/mmu.c | 3 +-- 3 files changed, 4 insertions(+), 4 deletions(-)