/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2019 FORTH-ICS/CARV
* Nick Kossifidis <[email protected]>
*/
#include <asm/asm.h> /* For RISCV_* and REG_* macros */
#include <asm/csr.h> /* For CSR_* macros */
#include <asm/page.h> /* For PAGE_SIZE */
#include <linux/linkage.h> /* For SYM_* macros */
.section ".rodata"
SYM_CODE_START(riscv_kexec_relocate)
/*
* s0: Pointer to the current entry
* s1: (const) Phys address to jump to after relocation
* s2: (const) Phys address of the FDT image
* s3: (const) The hartid of the current hart
* s4: (const) kernel_map.va_pa_offset, used when switching MMU off
* s5: Pointer to the destination address for the relocation
* s6: (const) Physical address of the main loop
*/
mv s0, a0
mv s1, a1
mv s2, a2
mv s3, a3
mv s4, a4
mv s5, zero
mv s6, zero
/* Disable / cleanup interrupts */
csrw CSR_SIE, zero
csrw CSR_SIP, zero
/*
* When we switch SATP.MODE to "Bare" we'll only
* play with physical addresses. However the first time
* we try to jump somewhere, the offset on the jump
* will be relative to pc which will still be on VA. To
* deal with this we set stvec to the physical address at
* the start of the loop below so that we jump there in
* any case.
*/
la s6, 1f
sub s6, s6, s4
csrw CSR_STVEC, s6
/*
* With C-extension, here we get 42 Bytes and the next
* .align directive would pad zeros here up to 44 Bytes.
* So manually put a nop here to avoid zeros padding.
*/
nop
/* Process entries in a loop */
.align 2
1:
REG_L t0, 0(s0) /* t0 = *image->entry */
addi s0, s0, RISCV_SZPTR /* image->entry++ */
/* IND_DESTINATION entry ? -> save destination address */
andi t1, t0, 0x1
beqz t1, 2f
andi s5, t0, ~0x1
j 1b
2:
/* IND_INDIRECTION entry ? -> update next entry ptr (PA) */
andi t1, t0, 0x2
beqz t1, 2f
andi s0, t0, ~0x2
csrw CSR_SATP, zero
jr s6
2:
/* IND_DONE entry ? -> jump to done label */
andi t1, t0, 0x4
beqz t1, 2f
j 4f
2:
/*
* IND_SOURCE entry ? -> copy page word by word to the
* destination address we got from IND_DESTINATION
*/
andi t1, t0, 0x8
beqz t1, 1b /* Unknown entry type, ignore it */
andi t0, t0, ~0x8
li t3, (PAGE_SIZE / RISCV_SZPTR) /* i = num words per page */
3: /* copy loop */
REG_L t1, (t0) /* t1 = *src_ptr */
REG_S t1, (s5) /* *dst_ptr = *src_ptr */
addi t0, t0, RISCV_SZPTR /* stc_ptr++ */
addi s5, s5, RISCV_SZPTR /* dst_ptr++ */
addi t3, t3, -0x1 /* i-- */
beqz t3, 1b /* copy done ? */
j 3b
4:
/* Pass the arguments to the next kernel / Cleanup*/
mv a0, s3
mv a1, s2
mv a2, s1
/* Cleanup */
mv a3, zero
mv a4, zero
mv a5, zero
mv a6, zero
mv a7, zero
mv s0, zero
mv s1, zero
mv s2, zero
mv s3, zero
mv s4, zero
mv s5, zero
mv s6, zero
mv s7, zero
mv s8, zero
mv s9, zero
mv s10, zero
mv s11, zero
mv t0, zero
mv t1, zero
mv t2, zero
mv t3, zero
mv t4, zero
mv t5, zero
mv t6, zero
csrw CSR_SEPC, zero
csrw CSR_SCAUSE, zero
csrw CSR_SSCRATCH, zero
/*
* Make sure the relocated code is visible
* and jump to the new kernel
*/
fence.i
jr a2
SYM_CODE_END(riscv_kexec_relocate)
riscv_kexec_relocate_end:
/* Used for jumping to crashkernel */
.section ".text"
SYM_CODE_START(riscv_kexec_norelocate)
/*
* s0: (const) Phys address to jump to
* s1: (const) Phys address of the FDT image
* s2: (const) The hartid of the current hart
*/
mv s0, a1
mv s1, a2
mv s2, a3
/* Disable / cleanup interrupts */
csrw CSR_SIE, zero
csrw CSR_SIP, zero
/* Pass the arguments to the next kernel / Cleanup*/
mv a0, s2
mv a1, s1
mv a2, s0
/* Cleanup */
mv a3, zero
mv a4, zero
mv a5, zero
mv a6, zero
mv a7, zero
mv s0, zero
mv s1, zero
mv s2, zero
mv s3, zero
mv s4, zero
mv s5, zero
mv s6, zero
mv s7, zero
mv s8, zero
mv s9, zero
mv s10, zero
mv s11, zero
mv t0, zero
mv t1, zero
mv t2, zero
mv t3, zero
mv t4, zero
mv t5, zero
mv t6, zero
csrw CSR_SEPC, zero
csrw CSR_SCAUSE, zero
csrw CSR_SSCRATCH, zero
/*
* Switch to physical addressing
* This will also trigger a jump to CSR_STVEC
* which in this case is the address of the new
* kernel.
*/
csrw CSR_STVEC, a2
csrw CSR_SATP, zero
SYM_CODE_END(riscv_kexec_norelocate)
.section ".rodata"
SYM_DATA(riscv_kexec_relocate_size,
.long riscv_kexec_relocate_end - riscv_kexec_relocate)
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