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powerpc/64s: Patch barrier_nospec in modules

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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 <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michal Suchanek 2018-04-24 14:15:56 +10:00 committed by Michael Ellerman
parent 2eea7f067f
commit 815069ca57
4 changed files with 27 additions and 4 deletions
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7
arch/powerpc/include/asm/setup.h
View File

@ -53,6 +53,13 @@ enum l1d_flush_type {
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);
extern bool barrier_nospec_enabled;
#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__ */

6
arch/powerpc/kernel/module.c
View File

@ -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(barrier_nospec_enabled,
(void *)sect->sh_addr,
(void *)sect->sh_addr + sect->sh_size);
#endif
sect = find_section(hdr, sechdrs, "__lwsync_fixup");

2
arch/powerpc/kernel/security.c
View File

@ -14,7 +14,7 @@
unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
static bool barrier_nospec_enabled;
bool barrier_nospec_enabled;
static void enable_barrier_nospec(bool enable)
{

16
arch/powerpc/lib/feature-fixups.c
View File

@ -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)