3.16.48-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Marc Zyngier <[email protected]> commit d68c1f7fd1b7148dab5fe658321d511998969f2d upstream. __do_hyp_init has the rather bad habit of ignoring RES1 bits and writing them back as zero. On a v8.0-8.2 CPU, this doesn't do anything bad, but may end-up being pretty nasty on future revisions of the architecture. Let's preserve those bits so that we don't have to fix this later on. Signed-off-by: Marc Zyngier <[email protected]> Signed-off-by: Christoffer Dall <[email protected]> [bwh: Backported to 3.16: - s/ELx/EL2/ - Adjust filename, context] Signed-off-by: Ben Hutchings <[email protected]> --- --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -89,6 +89,11 @@ #define SCTLR_EL2_C (1 << 2) #define SCTLR_EL2_A (1 << 1) #define SCTLR_EL2_M 1 + +#define SCTLR_EL2_RES1 ((1 << 4) | (1 << 5) | (1 << 11) | (1 << 16) | \ + (1 << 16) | (1 << 18) | (1 << 22) | (1 << 23) | \ + (1 << 28) | (1 << 29)) + #define SCTLR_EL2_FLAGS (SCTLR_EL2_M | SCTLR_EL2_A | SCTLR_EL2_C | \ SCTLR_EL2_SA | SCTLR_EL2_I) --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -84,10 +84,12 @@ __do_hyp_init: tlbi alle2 dsb sy - mrs x4, sctlr_el2 - and x4, x4, #SCTLR_EL2_EE // preserve endianness of EL2 - ldr x5, =SCTLR_EL2_FLAGS - orr x4, x4, x5 + /* + * Preserve all the RES1 bits while setting the default flags, + * as well as the EE bit on BE. + */ + ldr x4, =(SCTLR_EL2_RES1 | SCTLR_EL2_FLAGS) +CPU_BE( orr x4, x4, #SCTLR_EL2_EE) msr sctlr_el2, x4 isb
