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authorMark Rutland <mark.rutland@arm.com>2020-11-03 10:22:29 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2020-11-10 17:30:40 +0000
commit833be850f1cabd0e3b5337c0fcab20a6e936dd48 (patch)
treef19034fb5146f82b4fc2944ec86fef62581335aa /arch/arm64/include/asm/uaccess.h
parentba090f9cafd53dbabe0f0a8c4ccae44203d3731b (diff)
downloadlinux-833be850f1cabd0e3b5337c0fcab20a6e936dd48.tar.bz2
arm64: consistently use reserved_pg_dir
Depending on configuration options and specific code paths, we either use the empty_zero_page or the configuration-dependent reserved_ttbr0 as a reserved value for TTBR{0,1}_EL1. To simplify this code, let's always allocate and use the same reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated (and hence pre-zeroed), and is also marked as read-only in the kernel Image mapping. Keeping this separate from the empty_zero_page potentially helps with robustness as the empty_zero_page is used in a number of cases where a failure to map it read-only could allow it to become corrupted. The (presently unused) swapper_pg_end symbol is also removed, and comments are added wherever we rely on the offsets between the pre-allocated pg_dirs to keep these cases easily identifiable. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
-rw-r--r--arch/arm64/include/asm/uaccess.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 991dd5f031e4..385a189f7d39 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -113,8 +113,8 @@ static inline void __uaccess_ttbr0_disable(void)
local_irq_save(flags);
ttbr = read_sysreg(ttbr1_el1);
ttbr &= ~TTBR_ASID_MASK;
- /* reserved_ttbr0 placed before swapper_pg_dir */
- write_sysreg(ttbr - RESERVED_TTBR0_SIZE, ttbr0_el1);
+ /* reserved_pg_dir placed before swapper_pg_dir */
+ write_sysreg(ttbr - PAGE_SIZE, ttbr0_el1);
isb();
/* Set reserved ASID */
write_sysreg(ttbr, ttbr1_el1);