diff options
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/start.S | 78 |
1 files changed, 77 insertions, 1 deletions
diff --git a/arch/arm64/kernel/start.S b/arch/arm64/kernel/start.S index 2d4b5c0..969830d 100644 --- a/arch/arm64/kernel/start.S +++ b/arch/arm64/kernel/start.S @@ -147,6 +147,11 @@ c_entry: ldr x0, =__stack_top mov sp, x0 + /* export the spin gate array address for the dtb patcher */ + adr x0, tb_spin_gates + adrp x1, tb_spin_gates_ptr + str x0, [x1, #:lo12:tb_spin_gates_ptr] + /* clear bss */ ldr x0, =__bss_start ldr x1, =__bss_end @@ -166,9 +171,44 @@ c_entry: bl tashaboot_main /* if main returns there is nothing sensible to do */ +/* + * the spin table pen, the Wait For Event mechanism from the manual + * (B2-144, D1-2255). each secondary watches its own gate, the + * cpu-release-addr the dtb names. WFE clears the event register and + * sleeps, the kernel writes the secondary entry to the gate, makes + * it visible, then SEV sets the event register on every PE. the load + * recheck after each wake covers a release that lands between the + * load and the WFE. entered with MMU and caches off, left the same. + */ +.globl park_ret +park_ret: park: + adr x0, tb_spin_gates + mrs x1, mpidr_el1 + and x1, x1, #0xff /* affinity 0, the core number */ + add x0, x0, x1, lsl #3 /* gate = gates + core * 8 */ + + /* diagnostic: stamp arrival, primary prints it later */ + adr x3, tb_pen_stamps + strb w1, [x3, x1] + sevl wfe - b park + sevl + wfe + +1: + ldr x2, [x0] + cbnz x2, 2f + wfe + b 1b +2: + mov x0, xzr /* secondaries enter with x0-x3 zero */ + mov x1, xzr + mov x2, xzr + mov x3, xzr + dsb sy + isb + br x2 /* * exception vectors, the armv8 layout: 16 slots, 128 bytes each, in @@ -218,6 +258,19 @@ vectors: .align 7 b exc_serr +.pushsection .data.tb_spin, "aw" +.align 3 +.globl tb_spin_gates +tb_spin_gates: + .quad 0, 0, 0, 0, 0, 0, 0, 0 +.globl tb_spin_gates_ptr +tb_spin_gates_ptr: + .quad 0 +.globl tb_pen_stamps +tb_pen_stamps: + .byte 0, 0, 0, 0, 0, 0, 0, 0 +.popsection + exc_sync: stp x29, x30, [sp, #-16]! mov x29, sp @@ -226,6 +279,10 @@ exc_sync: cmp x3, #2 b.lt 1f mrs x0, esr_el2 + mrs x2, elr_el2 + lsr x1, x0, #26 + cmp x1, #0x16 /* HVC from lower EL */ + b.eq hvc_from_el1 mrs x1, far_el2 b 2f 1: @@ -237,6 +294,25 @@ exc_sync: ldp x29, x30, [sp], #16 b park +/* + * HVC from EL1, the PSCI conduit. x0-x3 are the PSCI args in the + * caller registers, dispatch and return in x0. ELR_EL2 is already + * the resume point, eret takes it back. + */ +hvc_from_el1: + stp x4, x5, [sp, #-16]! + stp x6, x7, [sp, #-16]! + stp x29, x30, [sp, #-16]! + mov x29, sp + + bl tb_psci_dispatch + + ldp x29, x30, [sp], #16 + ldp x6, x7, [sp], #16 + ldp x4, x5, [sp], #16 + ldp x29, x30, [sp], #16 + eret + exc_serr: stp x29, x30, [sp, #-16]! mov x29, sp |