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-rw-r--r--arch/arm64/include/asm/fpsimd.h12
-rw-r--r--arch/arm64/kernel/ptrace.c3
2 files changed, 8 insertions, 7 deletions
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 50e5f25d3024..481d94416d69 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -62,13 +62,13 @@ static inline void cpacr_restore(unsigned long cpacr)
* When we defined the maximum SVE vector length we defined the ABI so
* that the maximum vector length included all the reserved for future
* expansion bits in ZCR rather than those just currently defined by
- * the architecture. While SME follows a similar pattern the fact that
- * it includes a square matrix means that any allocations that attempt
- * to cover the maximum potential vector length (such as happen with
- * the regset used for ptrace) end up being extremely large. Define
- * the much lower actual limit for use in such situations.
+ * the architecture. Using this length to allocate worst size buffers
+ * results in excessively large allocations, and this effect is even
+ * more pronounced for SME due to ZA. Define more suitable VLs for
+ * these situations.
*/
-#define SME_VQ_MAX 16
+#define ARCH_SVE_VQ_MAX ((ZCR_ELx_LEN_MASK >> ZCR_ELx_LEN_SHIFT) + 1)
+#define SME_VQ_MAX ((SMCR_ELx_LEN_MASK >> SMCR_ELx_LEN_SHIFT) + 1)
struct task_struct;
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index dc6cf0e37194..e3bef38fc2e2 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1500,7 +1500,8 @@ static const struct user_regset aarch64_regsets[] = {
#ifdef CONFIG_ARM64_SVE
[REGSET_SVE] = { /* Scalable Vector Extension */
.core_note_type = NT_ARM_SVE,
- .n = DIV_ROUND_UP(SVE_PT_SIZE(SVE_VQ_MAX, SVE_PT_REGS_SVE),
+ .n = DIV_ROUND_UP(SVE_PT_SIZE(ARCH_SVE_VQ_MAX,
+ SVE_PT_REGS_SVE),
SVE_VQ_BYTES),
.size = SVE_VQ_BYTES,
.align = SVE_VQ_BYTES,