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Message-ID: <5deb67090b214f0e6eae96b7c406546d1a16f89b.1724309198.git.christophe.leroy@csgroup.eu>
Date: Thu, 22 Aug 2024 09:13:13 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Naveen N Rao <naveen@...nel.org>,
Andy Lutomirski <luto@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
x86@...nel.org,
"H. Peter Anvin" <hpa@...or.com>,
"Theodore Ts'o" <tytso@....edu>,
"Jason A. Donenfeld" <Jason@...c4.com>,
Arnd Bergmann <arnd@...db.de>,
Andrew Morton <akpm@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Shuah Khan <shuah@...nel.org>
Cc: linuxppc-dev@...ts.ozlabs.org,
linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org,
linux-arch@...r.kernel.org,
linux-mm@...ck.org,
linux-trace-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org
Subject: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom
With the current implementation, __cvdso_getrandom_data() calls
memset(), which is unexpected in the VDSO.
Rewrite opaque data initialisation to avoid memset().
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
lib/vdso/getrandom.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
index cab153c5f9be..4a56f45141b4 100644
--- a/lib/vdso/getrandom.c
+++ b/lib/vdso/getrandom.c
@@ -4,6 +4,7 @@
*/
#include <linux/minmax.h>
+#include <linux/array_size.h>
#include <vdso/datapage.h>
#include <vdso/getrandom.h>
#include <vdso/unaligned.h>
@@ -74,11 +75,15 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
u32 counter[2] = { 0 };
if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags)) {
- *(struct vgetrandom_opaque_params *)opaque_state = (struct vgetrandom_opaque_params) {
- .size_of_opaque_state = sizeof(*state),
- .mmap_prot = PROT_READ | PROT_WRITE,
- .mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS
- };
+ struct vgetrandom_opaque_params *params = opaque_state;
+ int i;
+
+ params->size_of_opaque_state = sizeof(*state);
+ params->mmap_prot = PROT_READ | PROT_WRITE;
+ params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+ for (i = 0; i < ARRAY_SIZE(params->reserved); i++)
+ params->reserved[i] = 0;
+
return 0;
}
--
2.44.0
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