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arm64: alternatives: use tpidr_el2 on VHE hosts

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Now that KVM uses tpidr_el2 in the same way as Linux's cpu_offset in
tpidr_el1, merge the two. This saves KVM from save/restoring tpidr_el1
on VHE hosts, and allows future code to blindly access per-cpu variables
without triggering world-switch.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
James Morse
2018-01-08 15:38:06 +00:00
committed by Catalin Marinas
parent c97e166e54
commit 6d99b68933
6 changed files with 49 additions and 6 deletions
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9
arch/arm64/kernel/alternative.c
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@@ -32,6 +32,8 @@
#define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset)
#define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset)
int alternatives_applied;
struct alt_region {
struct alt_instr *begin;
struct alt_instr *end;
@@ -143,7 +145,6 @@ static void __apply_alternatives(void *alt_region, bool use_linear_alias)
*/
static int __apply_alternatives_multi_stop(void *unused)
{
static int patched = 0;
struct alt_region region = {
.begin = (struct alt_instr *)__alt_instructions,
.end = (struct alt_instr *)__alt_instructions_end,
@@ -151,14 +152,14 @@ static int __apply_alternatives_multi_stop(void *unused)
/* We always have a CPU 0 at this point (__init) */
if (smp_processor_id()) {
while (!READ_ONCE(patched))
while (!READ_ONCE(alternatives_applied))
cpu_relax();
isb();
} else {
BUG_ON(patched);
BUG_ON(alternatives_applied);
__apply_alternatives(&region, true);
/* Barriers provided by the cache flushing */
WRITE_ONCE(patched, 1);
WRITE_ONCE(alternatives_applied, 1);
}
return 0;