diff options
Diffstat (limited to 'arch/arm/kernel/efi_phys.S')
| -rw-r--r-- | arch/arm/kernel/efi_phys.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/arm/kernel/efi_phys.S b/arch/arm/kernel/efi_phys.S new file mode 100644 index 000000000000..e36cc17a17a2 --- /dev/null +++ b/arch/arm/kernel/efi_phys.S @@ -0,0 +1,59 @@ +/* + * arch/arm/kernel/efi_phys.S + * + * Copyright (C) 2013 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/linkage.h> +#define PAR_MASK 0xfff + + .text +@ efi_phys_call(a, b, c, d, *f) + .align 5 + .pushsection .idmap.text, "ax" +ENTRY(efi_phys_call) + @ Save physical context + mov r12, sp + push {r4-r5, r12, lr} + + @ Extract function pointer (don't write r12 beyond this) + ldr r12, [sp, #16] + + @ Convert sp to 32-bit physical + mov lr, sp + ldr r4, =PAR_MASK + and r5, lr, r4 @ Extract lower 12 bits of sp + mcr p15, 0, lr, c7, c8, 1 @ Write VA -> ATS1CPW + mrc p15, 0, lr, c7, c4, 0 @ Physical Address Register + mvn r4, r4 + and lr, lr, r4 @ Clear lower 12 bits of PA + add lr, lr, r5 @ Calculate phys sp + mov sp, lr @ Update + + @ Disable MMU + mrc p15, 0, lr, c1, c0, 0 @ ctrl register + bic lr, lr, #0x1 @ ...............m + mcr p15, 0, lr, c1, c0, 0 @ disable MMU + isb + + @ Make call + blx r12 + + pop {r4-r5, r12, lr} + + @ Enable MMU + Caches + mrc p15, 0, r1, c1, c0, 0 @ ctrl register + orr r1, r1, #0x1000 @ ...i............ + orr r1, r1, #0x0005 @ .............c.m + mcr p15, 0, r1, c1, c0, 0 @ enable MMU + isb + + @ Restore virtual sp and return + mov sp, r12 + bx lr +ENDPROC(efi_phys_call) + .popsection |