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arm64: Add support for read and write registers at current EL in assembly

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In order to ease the process of reading and writing any register at current EL,
provide read_current and write_current assembly macros. These are included in
arch/lib_helpers.h under the __ASSEMBLY__ macro condition. This is done to allow
the same header file to be included by .c and .S files.

BUG=chrome-os-partner:30785
BRANCH=None
TEST=Compiles successfully

Change-Id: I1258850438624abfe3b1ed7240df0db0e7905be6
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/216373
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Tom Warren <twarren@nvidia.com>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
This commit is contained in:
Furquan Shaikh 2014-08-31 12:21:37 -07:00 • committed by chrome-internal-fetch
commit c11c7287f5
1 changed files with 97 additions and 0 deletions
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97
src/arch/arm64/include/armv8/arch/lib_helpers.h
View file

@ -30,6 +30,9 @@
* file.
*/
#ifndef __ARCH_LIB_HELPERS_H__
#define __ARCH_LIB_HELPERS_H__
#define EL0 0
#define EL1 1
#define EL2 2
@ -38,6 +41,96 @@
#define CURRENT_EL_MASK 0x3
#define CURRENT_EL_SHIFT 2
#ifdef __ASSEMBLY__
/* Macro to switch to label based on current el */
.macro switch_el xreg label1 label2 label3
mrs \xreg, CurrentEL
/* Currently at EL1 */
cmp \xreg, #(EL1 << CURRENT_EL_SHIFT)
b.eq \label1
/* Currently at EL2 */
cmp \xreg, #(EL2 << CURRENT_EL_SHIFT)
b.eq \label2
/* Currently at EL3 */
cmp \xreg, #(EL3 << CURRENT_EL_SHIFT)
b.eq \label3
.endm
/* Macro to read sysreg at current EL
xreg - reg in which read value needs to be stored
sysreg - system reg that is to be read
*/
.macro read_current xreg sysreg
switch_el \xreg, 101f, 102f, 103f
101:
mrs \xreg, \sysreg\()_el1
b 104f
102:
mrs \xreg, \sysreg\()_el2
b 104f
103:
mrs \xreg, \sysreg\()_el3
b 104f
104:
.endm
/* Macro to write sysreg at current EL
xreg - reg from which value needs to be written
sysreg - system reg that is to be written
temp - temp reg that can be used to read current EL
*/
.macro write_current sysreg xreg temp
switch_el \temp, 101f, 102f, 103f
101:
msr \sysreg\()_el1, \xreg
b 104f
102:
msr \sysreg\()_el2, \xreg
b 104f
103:
msr \sysreg\()_el3, \xreg
b 104f
104:
.endm
/* Macro to read sysreg at current EL - 1
xreg - reg in which read value needs to be stored
sysreg - system reg that is to be read
*/
.macro read_lower xreg sysreg
switch_el \xreg, 101f, 102f, 103f
101:
b 104f
102:
mrs \xreg, \sysreg\()_el1
b 104f
103:
mrs \xreg, \sysreg\()_el2
b 104f
104:
.endm
/* Macro to write sysreg at current EL - 1
xreg - reg from which value needs to be written
sysreg - system reg that is to be written
temp - temp reg that can be used to read current EL
*/
.macro write_lower sysreg xreg temp
switch_el \temp, 101f, 102f, 103f
101:
b 104f
102:
msr \sysreg\()_el1, \xreg
b 104f
103:
msr \sysreg\()_el2, \xreg
b 104f
104:
.endm
#else
#define DAIF_DBG_BIT (1<<3)
#define DAIF_ABT_BIT (1<<2)
#define DAIF_IRQ_BIT (1<<1)
@ -298,3 +391,7 @@ void tlbiallis_el2(void);
void tlbiallis_el3(void);
void tlbiallis_current(void);
void tlbivaa_el1(uint64_t va);
#endif // __ASSEMBLY__
#endif // __ARCH_LIB_HELPERS_H__