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| author | Marc Zyngier <marc.zyngier@arm.com> | 2014-02-19 13:33:14 +0400 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2016-02-29 21:34:18 +0300 |
| commit | 1f364c8c48a0767885a18451ee074c64b454157a (patch) | |
| tree | 3fa0d98862ed916c5b2767c6015fa563d89c2857 /arch/arm64/kernel/head.S | |
| parent | ae7e27fe6834d4a78fd8e4576a8e1dd15ae0c008 (diff) | |
| download | linux-1f364c8c48a0767885a18451ee074c64b454157a.tar.xz | |
arm64: VHE: Add support for running Linux in EL2 mode
With ARMv8.1 VHE, the architecture is able to (almost) transparently
run the kernel at EL2, despite being written for EL1.
This patch takes care of the "almost" part, mostly preventing the kernel
from dropping from EL2 to EL1, and setting up the HYP configuration.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 917d98108b3f..6f2f37743d3b 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -30,6 +30,7 @@ #include <asm/cache.h> #include <asm/cputype.h> #include <asm/kernel-pgtable.h> +#include <asm/kvm_arm.h> #include <asm/memory.h> #include <asm/pgtable-hwdef.h> #include <asm/pgtable.h> @@ -464,9 +465,27 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1 isb ret +2: +#ifdef CONFIG_ARM64_VHE + /* + * Check for VHE being present. For the rest of the EL2 setup, + * x2 being non-zero indicates that we do have VHE, and that the + * kernel is intended to run at EL2. + */ + mrs x2, id_aa64mmfr1_el1 + ubfx x2, x2, #8, #4 +#else + mov x2, xzr +#endif + /* Hyp configuration. */ -2: mov x0, #(1 << 31) // 64-bit EL1 + mov x0, #HCR_RW // 64-bit EL1 + cbz x2, set_hcr + orr x0, x0, #HCR_TGE // Enable Host Extensions + orr x0, x0, #HCR_E2H +set_hcr: msr hcr_el2, x0 + isb /* Generic timers. */ mrs x0, cnthctl_el2 @@ -526,6 +545,13 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems /* Stage-2 translation */ msr vttbr_el2, xzr + cbz x2, install_el2_stub + + mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2 + isb + ret + +install_el2_stub: /* Hypervisor stub */ adrp x0, __hyp_stub_vectors add x0, x0, #:lo12:__hyp_stub_vectors |