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| author | Matthew Leach <matthew.leach@arm.com> | 2013-10-11 17:52:18 +0400 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2013-10-25 18:59:42 +0400 |
| commit | 710be9ac4ea0d2e02a2c4aa625795e65bf3db5b1 (patch) | |
| tree | 8dce60344b354cfab9e78b62e223c413f7e6bae4 /arch/arm64/kernel | |
| parent | 9cf71728931a4073b9e3a4bcbf9dada86bc98370 (diff) | |
| download | linux-710be9ac4ea0d2e02a2c4aa625795e65bf3db5b1.tar.xz | |
arm64: big-endian: write CPU holding pen address as LE
Currently when CPUs are brought online via a spin-table, the address
they should jump to is written to the cpu-release-addr in the kernel's
native endianness. As the kernel may switch endianness, secondaries
might read the value byte-reversed from what was intended, and they
would jump to the wrong address.
As the only current arm64 spin-table implementations are
little-endian, stricten up the arm64 spin-table definition such that
the value written to cpu-release-addr is _always_ little-endian
regardless of the endianness of any CPU. If a spinning CPU is
operating big-endian, it must byte-reverse the value before jumping to
handle this.
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/smp_spin_table.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c index 27f08367a6e7..44c22805d2e2 100644 --- a/arch/arm64/kernel/smp_spin_table.c +++ b/arch/arm64/kernel/smp_spin_table.c @@ -72,7 +72,16 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu) return -ENODEV; release_addr = __va(cpu_release_addr[cpu]); - release_addr[0] = (void *)__pa(secondary_holding_pen); + + /* + * We write the release address as LE regardless of the native + * endianess of the kernel. Therefore, any boot-loaders that + * read this address need to convert this address to the + * boot-loader's endianess before jumping. This is mandated by + * the boot protocol. + */ + release_addr[0] = (void *) cpu_to_le64(__pa(secondary_holding_pen)); + __flush_dcache_area(release_addr, sizeof(release_addr[0])); /* |