From e6a9522ac3ff59980ea00e070b6b8573aface36a Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 25 Jul 2019 15:29:57 -0500 Subject: drm/i915: Remove redundant user_access_end() from __copy_from_user() error path Objtool reports: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x36: redundant UACCESS disable __copy_from_user() already does both STAC and CLAC, so the user_access_end() in its error path adds an extra unnecessary CLAC. Fixes: 0b2c8f8b6b0c ("i915: fix missing user_access_end() in page fault exception case") Reported-by: Thomas Gleixner Reported-by: Sedat Dilek Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Tested-by: Nick Desaulniers Tested-by: Sedat Dilek Acked-by: Peter Zijlstra (Intel) Acked-by: Chris Wilson Link: https://github.com/ClangBuiltLinux/linux/issues/617 Link: https://lkml.kernel.org/r/51a4155c5bc2ca847a9cbe85c1c11918bb193141.1564086017.git.jpoimboe@redhat.com --- drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 5fae0e50aad0..41dab9ea33cd 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -1628,6 +1628,7 @@ static int check_relocations(const struct drm_i915_gem_exec_object2 *entry) static int eb_copy_relocations(const struct i915_execbuffer *eb) { + struct drm_i915_gem_relocation_entry *relocs; const unsigned int count = eb->buffer_count; unsigned int i; int err; @@ -1635,7 +1636,6 @@ static int eb_copy_relocations(const struct i915_execbuffer *eb) for (i = 0; i < count; i++) { const unsigned int nreloc = eb->exec[i].relocation_count; struct drm_i915_gem_relocation_entry __user *urelocs; - struct drm_i915_gem_relocation_entry *relocs; unsigned long size; unsigned long copied; @@ -1663,14 +1663,8 @@ static int eb_copy_relocations(const struct i915_execbuffer *eb) if (__copy_from_user((char *)relocs + copied, (char __user *)urelocs + copied, - len)) { -end_user: - user_access_end(); -end: - kvfree(relocs); - err = -EFAULT; - goto err; - } + len)) + goto end; copied += len; } while (copied < size); @@ -1699,10 +1693,14 @@ end: return 0; +end_user: + user_access_end(); +end: + kvfree(relocs); + err = -EFAULT; err: while (i--) { - struct drm_i915_gem_relocation_entry *relocs = - u64_to_ptr(typeof(*relocs), eb->exec[i].relocs_ptr); + relocs = u64_to_ptr(typeof(*relocs), eb->exec[i].relocs_ptr); if (eb->exec[i].relocation_count) kvfree(relocs); } -- cgit v1.2.3-59-g8ed1b