On Tue, 24 Apr 2018 14:15:56 +1000
Michael Ellerman <m...@ellerman.id.au> wrote:
> From: Michal Suchanek <msucha...@suse.de>
>
> Note that unlike RFI which is patched only in kernel the nospec state
> reflects settings at the time the module was loaded.
>
> Iterating all modules and re-patching every time the settings change
> is not implemented.
>
> Based on lwsync patching.
>
> Signed-off-by: Michal Suchanek <msucha...@suse.de>
> Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
> ---
> arch/powerpc/include/asm/setup.h | 6 ++++++
> arch/powerpc/kernel/module.c | 6 ++++++
> arch/powerpc/lib/feature-fixups.c | 16 +++++++++++++---
> 3 files changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/setup.h
> b/arch/powerpc/include/asm/setup.h index afc7280cce3b..4335cddc1cf2
> 100644 --- a/arch/powerpc/include/asm/setup.h
> +++ b/arch/powerpc/include/asm/setup.h
> @@ -54,6 +54,12 @@ void setup_rfi_flush(enum l1d_flush_type, bool
> enable); void do_rfi_flush_fixups(enum l1d_flush_type types);
> void do_barrier_nospec_fixups(bool enable);
>
> +#ifdef CONFIG_PPC_BOOK3S_64
> +void do_barrier_nospec_fixups_range(bool enable, void *start, void
> *end); +#else
> +static inline void do_barrier_nospec_fixups_range(bool enable, void
> *start, void *end) { }; +#endif
> +
> #endif /* !__ASSEMBLY__ */
>
> #endif /* _ASM_POWERPC_SETUP_H */
> diff --git a/arch/powerpc/kernel/module.c
> b/arch/powerpc/kernel/module.c index 3f7ba0f5bf29..a72698cd3dd0 100644
> --- a/arch/powerpc/kernel/module.c
> +++ b/arch/powerpc/kernel/module.c
> @@ -72,6 +72,12 @@ int module_finalize(const Elf_Ehdr *hdr,
> do_feature_fixups(powerpc_firmware_features,
> (void *)sect->sh_addr,
> (void *)sect->sh_addr +
> sect->sh_size); +
> + sect = find_section(hdr, sechdrs, "__spec_barrier_fixup");
> + if (sect != NULL)
> + do_barrier_nospec_fixups_range(true,
This saves a global but always patches modules with the ORI
flush. The patching also produces a log message which can be confusing
to the user. Even when barrier is disabled "barrier-nospec: using ORI
speculation barrier" is logged when modules are loaded.
For consistency when debugging the settings I would suggest to keep the
export.
It is also no longer consistent with the commit message.
Thanks
Michal
> + (void *)sect->sh_addr,
> + (void *)sect->sh_addr +
> sect->sh_size); #endif
>
> sect = find_section(hdr, sechdrs, "__lwsync_fixup");
> diff --git a/arch/powerpc/lib/feature-fixups.c
> b/arch/powerpc/lib/feature-fixups.c index 093c1d2ea5fd..3b37529f82f8
> 100644 --- a/arch/powerpc/lib/feature-fixups.c
> +++ b/arch/powerpc/lib/feature-fixups.c
> @@ -163,14 +163,14 @@ void do_rfi_flush_fixups(enum l1d_flush_type
> types) : "unknown");
> }
>
> -void do_barrier_nospec_fixups(bool enable)
> +void do_barrier_nospec_fixups_range(bool enable, void *fixup_start,
> void *fixup_end) {
> unsigned int instr, *dest;
> long *start, *end;
> int i;
>
> - start = PTRRELOC(&__start___barrier_nospec_fixup),
> - end = PTRRELOC(&__stop___barrier_nospec_fixup);
> + start = fixup_start;
> + end = fixup_end;
>
> instr = 0x60000000; /* nop */
>
> @@ -189,6 +189,16 @@ void do_barrier_nospec_fixups(bool enable)
> printk(KERN_DEBUG "barrier-nospec: patched %d locations\n",
> i); }
>
> +void do_barrier_nospec_fixups(bool enable)
> +{
> + void *start, *end;
> +
> + start = PTRRELOC(&__start___barrier_nospec_fixup),
> + end = PTRRELOC(&__stop___barrier_nospec_fixup);
> +
> + do_barrier_nospec_fixups_range(enable, start, end);
> +}
> +
> #endif /* CONFIG_PPC_BOOK3S_64 */
>
> void do_lwsync_fixups(unsigned long value, void *fixup_start, void
> *fixup_end)
