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| author | Lukas Wunner <lukas@wunner.de> | 2024-04-07 19:57:40 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2024-04-12 15:07:53 +0800 |
| commit | 5c6ca9d936654a135b459c846885e08966e5e5bf (patch) | |
| tree | acc27f18100f7d7d732deb83c58bfc10892d38e8 /include | |
| parent | c9ccfd5e0ff0dd929ce86d1b5f3c6a414110947a (diff) | |
| download | linux-stable-5c6ca9d936654a135b459c846885e08966e5e5bf.tar.gz linux-stable-5c6ca9d936654a135b459c846885e08966e5e5bf.tar.bz2 linux-stable-5c6ca9d936654a135b459c846885e08966e5e5bf.zip | |
X.509: Introduce scope-based x509_certificate allocation
Add a DEFINE_FREE() clause for x509_certificate structs and use it in
x509_cert_parse() and x509_key_preparse(). These are the only functions
where scope-based x509_certificate allocation currently makes sense.
A third user will be introduced with the forthcoming SPDM library
(Security Protocol and Data Model) for PCI device authentication.
Unlike most other DEFINE_FREE() clauses, this one checks for IS_ERR()
instead of NULL before calling x509_free_certificate() at end of scope.
That's because the "constructor" of x509_certificate structs,
x509_cert_parse(), returns a valid pointer or an ERR_PTR(), but never
NULL.
Comparing the Assembler output before/after has shown they are identical,
save for the fact that gcc-12 always generates two return paths when
__cleanup() is used, one for the success case and one for the error case.
In x509_cert_parse(), add a hint for the compiler that kzalloc() never
returns an ERR_PTR(). Otherwise the compiler adds a gratuitous IS_ERR()
check on return. Introduce an assume() macro for this which can be
re-used elsewhere in the kernel to provide hints for the compiler.
Suggested-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Link: https://lore.kernel.org/all/20231003153937.000034ca@Huawei.com/
Link: https://lwn.net/Articles/934679/
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/compiler.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index c00cc6c0878a..53666eb19909 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -148,6 +148,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, } while (0) #endif +#define assume(cond) do { if (!(cond)) __builtin_unreachable(); } while (0) + /* * KENTRY - kernel entry point * This can be used to annotate symbols (functions or data) that are used |