From 56583c9a1400fe1935edd55b24b4fbbc779b59cb Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 23 Sep 2017 14:59:51 +0200 Subject: [PATCH] x86/fpu: Clarify parameter names in the copy_xstate_to_*() methods Right now there's a confusing mixture of 'offset' and 'size' parameters: - __copy_xstate_to_*() input parameter 'end_pos' not not really an offset, but the full size of the copy to be performed. - input parameter 'count' to copy_xstate_to_*() shadows that of __copy_xstate_to_*()'s 'count' parameter name - but the roles are different: the first one is the total number of bytes to be copied, while the second one is a partial copy size. To unconfuse all this, use a consistent set of parameter names: - 'size' is the partial copy size within a single xstate component - 'size_total' is the total copy requested - 'offset_start' is the requested starting offset. - 'offset' is the offset within an xstate component. No change in functionality. Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Eric Biggers Cc: Fenghua Yu Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/20170923130016.21448-9-mingo@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/xstate.h | 4 ++-- arch/x86/kernel/fpu/xstate.c | 44 +++++++++++++++++++-------------------- 2 files changed, 24 insertions(+), 24 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index e4430b84939d..fed6617a1079 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -48,8 +48,8 @@ void fpu__xstate_clear_all_cpu_caps(void); void *get_xsave_addr(struct xregs_state *xsave, int xstate); const void *get_xsave_field_ptr(int xstate_field); int using_compacted_format(void); -int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int pos, unsigned int count); -int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int pos, unsigned int count); +int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); +int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave); #endif diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 1f50fdaf4c5a..c13083579655 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -927,15 +927,15 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, static inline int __copy_xstate_to_kernel(void *kbuf, const void *data, - unsigned int pos, unsigned int count, int end_pos) + unsigned int offset, unsigned int size, int size_total) { - if (!count) + if (!size) return 0; - if (end_pos < 0 || pos < end_pos) { - unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos); + if (size_total < 0 || offset < size_total) { + unsigned int copy = size_total < 0 ? size : min(size, size_total - offset); - memcpy(kbuf + pos, data, copy); + memcpy(kbuf + offset, data, copy); } return 0; } @@ -947,7 +947,7 @@ __copy_xstate_to_kernel(void *kbuf, * It supports partial copy but pos always starts from zero. This is called * from xstateregs_get() and there we check the CPU has XSAVES. */ -int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int pos, unsigned int count) +int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total) { unsigned int offset, size; int ret, i; @@ -956,7 +956,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po /* * Currently copy_regset_to_user() starts from pos 0: */ - if (unlikely(pos != 0)) + if (unlikely(offset_start != 0)) return -EFAULT; /* @@ -972,7 +972,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po offset = offsetof(struct xregs_state, header); size = sizeof(header); - ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, count); + ret = __copy_xstate_to_kernel(kbuf, &header, offset, size, size_total); if (ret) return ret; @@ -986,11 +986,11 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po offset = xstate_offsets[i]; size = xstate_sizes[i]; - ret = __copy_xstate_to_kernel(kbuf, src, offset, size, count); + ret = __copy_xstate_to_kernel(kbuf, src, offset, size, size_total); if (ret) return ret; - if (offset + size >= count) + if (offset + size >= size_total) break; } @@ -1002,7 +1002,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po offset = offsetof(struct fxregs_state, sw_reserved); size = sizeof(xstate_fx_sw_bytes); - ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, count); + ret = __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total); if (ret) return ret; @@ -1010,15 +1010,15 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po } static inline int -__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, int end_pos) +__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, int size_total) { - if (!count) + if (!size) return 0; - if (end_pos < 0 || pos < end_pos) { - unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos); + if (size_total < 0 || offset < size_total) { + unsigned int copy = size_total < 0 ? size : min(size, size_total - offset); - if (__copy_to_user(ubuf + pos, data, copy)) + if (__copy_to_user(ubuf + offset, data, copy)) return -EFAULT; } return 0; @@ -1030,7 +1030,7 @@ __copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, uns * zero. This is called from xstateregs_get() and there we check the CPU * has XSAVES. */ -int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int pos, unsigned int count) +int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total) { unsigned int offset, size; int ret, i; @@ -1039,7 +1039,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i /* * Currently copy_regset_to_user() starts from pos 0: */ - if (unlikely(pos != 0)) + if (unlikely(offset_start != 0)) return -EFAULT; /* @@ -1055,7 +1055,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i offset = offsetof(struct xregs_state, header); size = sizeof(header); - ret = __copy_xstate_to_user(ubuf, &header, offset, size, count); + ret = __copy_xstate_to_user(ubuf, &header, offset, size, size_total); if (ret) return ret; @@ -1069,11 +1069,11 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i offset = xstate_offsets[i]; size = xstate_sizes[i]; - ret = __copy_xstate_to_user(ubuf, src, offset, size, count); + ret = __copy_xstate_to_user(ubuf, src, offset, size, size_total); if (ret) return ret; - if (offset + size >= count) + if (offset + size >= size_total) break; } @@ -1085,7 +1085,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i offset = offsetof(struct fxregs_state, sw_reserved); size = sizeof(xstate_fx_sw_bytes); - ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, count); + ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, size_total); if (ret) return ret; -- 2.11.0