diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2023-05-30 12:03:27 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-06-06 17:39:05 +0100 |
| commit | ea3752ba9685b47db4571ddaee39344cf2b0bf45 (patch) | |
| tree | 626f47a4c908fda78a5541be274cfd5ec7942e7b /arch/arm64/kernel/ftrace.c | |
| parent | e46b7103aef39c3f421f0bff7a10ae5a29cd5cee (diff) | |
arm64: module: mandate MODULE_PLTS
Contemporary kernels and modules can be relatively large, especially
when common debug options are enabled. Using GCC 12.1.0, a v6.3-rc7
defconfig kernel is ~38M, and with PROVE_LOCKING + KASAN_INLINE enabled
this expands to ~117M. Shanker reports [1] that the NVIDIA GPU driver
alone can consume 110M of module space in some configurations.
Both KASLR and ARM64_ERRATUM_843419 select MODULE_PLTS, so anyone
wanting a kernel to have KASLR or run on Cortex-A53 will have
MODULE_PLTS selected. This is the case in defconfig and distribution
kernels (e.g. Debian, Android, etc).
Practically speaking, this means we're very likely to need MODULE_PLTS
and while it's almost guaranteed that MODULE_PLTS will be selected, it
is possible to disable support, and we have to maintain some awkward
special cases for such unusual configurations.
This patch removes the MODULE_PLTS config option, with the support code
always enabled if MODULES is selected. This results in a slight
simplification, and will allow for further improvement in subsequent
patches.
For any config which currently selects MODULE_PLTS, there will be no
functional change as a result of this patch.
[1] https://lore.kernel.org/linux-arm-kernel/159ceeab-09af-3174-5058-445bc8dcf85b@nvidia.com/
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Shanker Donthineni <sdonthineni@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230530110328.2213762-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/ftrace.c')
| -rw-r--r-- | arch/arm64/kernel/ftrace.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 432626c866a8..a650f5e11fc5 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -197,7 +197,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) static struct plt_entry *get_ftrace_plt(struct module *mod) { -#ifdef CONFIG_ARM64_MODULE_PLTS +#ifdef CONFIG_MODULES struct plt_entry *plt = mod->arch.ftrace_trampolines; return &plt[FTRACE_PLT_IDX]; @@ -249,7 +249,7 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, * must use a PLT to reach it. We can only place PLTs for modules, and * only when module PLT support is built-in. */ - if (!IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) + if (!IS_ENABLED(CONFIG_MODULES)) return false; /* @@ -431,10 +431,8 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, * * Note: 'mod' is only set at module load time. */ - if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) && - IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && mod) { + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) && mod) return aarch64_insn_patch_text_nosync((void *)pc, new); - } if (!ftrace_find_callable_addr(rec, mod, &addr)) return -EINVAL; |