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authorPaolo Bonzini <[email protected]>2024-07-12 11:24:12 -0400
committerPaolo Bonzini <[email protected]>2024-07-12 11:24:12 -0400
commitc8b8b8190a80b591aa73c27c70a668799f8db547 (patch)
tree9d948c9aac89678abe64ac81f6c43348bf4b2091 /arch/arm64/kernel/syscall.c
parentf0a23883fad4ec8a63faddb9639a92be2e007624 (diff)
parent492ac37fa38faf520b5beae44c930063265ee183 (diff)
Merge tag 'loongarch-kvm-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD
LoongArch KVM changes for v6.11 1. Add ParaVirt steal time support. 2. Add some VM migration enhancement. 3. Add perf kvm-stat support for loongarch.
Diffstat (limited to 'arch/arm64/kernel/syscall.c')
-rw-r--r--arch/arm64/kernel/syscall.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index ad198262b981..7230f6e20ab8 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -53,17 +53,15 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno,
syscall_set_return_value(current, regs, 0, ret);
/*
- * Ultimately, this value will get limited by KSTACK_OFFSET_MAX(),
- * but not enough for arm64 stack utilization comfort. To keep
- * reasonable stack head room, reduce the maximum offset to 9 bits.
+ * This value will get limited by KSTACK_OFFSET_MAX(), which is 10
+ * bits. The actual entropy will be further reduced by the compiler
+ * when applying stack alignment constraints: the AAPCS mandates a
+ * 16-byte aligned SP at function boundaries, which will remove the
+ * 4 low bits from any entropy chosen here.
*
- * The actual entropy will be further reduced by the compiler when
- * applying stack alignment constraints: the AAPCS mandates a
- * 16-byte (i.e. 4-bit) aligned SP at function boundaries.
- *
- * The resulting 5 bits of entropy is seen in SP[8:4].
+ * The resulting 6 bits of entropy is seen in SP[9:4].
*/
- choose_random_kstack_offset(get_random_u16() & 0x1FF);
+ choose_random_kstack_offset(get_random_u16());
}
static inline bool has_syscall_work(unsigned long flags)