Patrick Georgi (pgeorgi@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/8801
-gerrit
commit 7f4d8ada54659b86fc17333d3a32f0a933871f84 Author: Furquan Shaikh furquan@google.com Date: Wed Aug 27 15:57:47 2014 -0700
libpayload arm64: Add support for read and write registers at current EL in assembly
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:31634 BRANCH=None TEST=Compiles successfully for ryu
Change-Id: I79241a944b68ebb24865e745a9835f54ab6d1a8f Signed-off-by: Patrick Georgi pgeorgi@chromium.org Original-Commit-Id: 2b55fbde466126c4de7f5f7bb2d1427196be842f Original-Change-Id: I678ab89c4aa1b08898166e135b5ab2d6453bb5e8 Original-Signed-off-by: Furquan Shaikh furquan@google.com Original-Reviewed-on: https://chromium-review.googlesource.com/214576 Original-Tested-by: Furquan Shaikh furquan@chromium.org Original-Reviewed-by: Aaron Durbin adurbin@chromium.org Original-Commit-Queue: Furquan Shaikh furquan@chromium.org --- .../libpayload/include/arm64/arch/lib_helpers.h | 57 ++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/payloads/libpayload/include/arm64/arch/lib_helpers.h b/payloads/libpayload/include/arm64/arch/lib_helpers.h index a8eb396..ca68435 100644 --- a/payloads/libpayload/include/arm64/arch/lib_helpers.h +++ b/payloads/libpayload/include/arm64/arch/lib_helpers.h @@ -33,6 +33,61 @@ #ifndef __ARCH_LIB_HELPERS_H__ #define __ARCH_LIB_HELPERS_H__
+#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, 0x4 + b.eq \label1 + /* Currently at EL2 */ + cmp \xreg, 0x8 + b.eq \label2 + /* Currently at EL3 */ + cmp \xreg, 0xc + 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 + +#else + #define EL0 0 #define EL1 1 #define EL2 2 @@ -347,4 +402,6 @@ void tlbivaa_el1(uint64_t va); /* Clock */ void set_cntfrq(uint32_t freq);
+#endif // __ASSEMBLY__ + #endif //__ARCH_LIB_HELPERS_H__