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a11c07f032
On kdump instead of using an intermediate step to relocate the kernel,
that lives in a "control buffer" outside the current kernel's mapping,
we jump to the crash kernel directly by calling riscv_kexec_norelocate().
The current implementation uses va_pa_offset while switching to physical
addressing, however since we moved the kernel outside the linear mapping
this won't work anymore since riscv_kexec_norelocate() is part of the
kernel mapping and we should use kernel_map.va_kernel_pa_offset, and also
take XIP kernel into account.
We don't really need to use va_pa_offset on riscv_kexec_norelocate, we
can just set STVEC to the physical address of the new kernel instead and
let the hart jump to the new kernel on the next instruction after setting
SATP to zero. This fixes kdump and is also simpler/cleaner.
I tested this on the latest qemu and HiFive Unmatched and works as
expected.
Fixes: 2bfc6cd81b ("riscv: Move kernel mapping outside of linear mapping")
Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Reviewed-by: Alexandre Ghiti <alex@ghiti.fr>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
222 lines
4.4 KiB
ArmAsm
222 lines
4.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2019 FORTH-ICS/CARV
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* Nick Kossifidis <mick@ics.forth.gr>
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*/
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#include <asm/asm.h> /* For RISCV_* and REG_* macros */
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#include <asm/csr.h> /* For CSR_* macros */
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#include <asm/page.h> /* For PAGE_SIZE */
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#include <linux/linkage.h> /* For SYM_* macros */
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.section ".rodata"
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SYM_CODE_START(riscv_kexec_relocate)
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/*
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* s0: Pointer to the current entry
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* s1: (const) Phys address to jump to after relocation
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* s2: (const) Phys address of the FDT image
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* s3: (const) The hartid of the current hart
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* s4: Pointer to the destination address for the relocation
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* s5: (const) Number of words per page
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* s6: (const) 1, used for subtraction
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* s7: (const) kernel_map.va_pa_offset, used when switching MMU off
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* s8: (const) Physical address of the main loop
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* s9: (debug) indirection page counter
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* s10: (debug) entry counter
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* s11: (debug) copied words counter
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*/
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mv s0, a0
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mv s1, a1
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mv s2, a2
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mv s3, a3
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mv s4, zero
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li s5, (PAGE_SIZE / RISCV_SZPTR)
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li s6, 1
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mv s7, a4
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mv s8, zero
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mv s9, zero
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mv s10, zero
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mv s11, zero
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/* Disable / cleanup interrupts */
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csrw CSR_SIE, zero
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csrw CSR_SIP, zero
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/*
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* When we switch SATP.MODE to "Bare" we'll only
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* play with physical addresses. However the first time
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* we try to jump somewhere, the offset on the jump
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* will be relative to pc which will still be on VA. To
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* deal with this we set stvec to the physical address at
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* the start of the loop below so that we jump there in
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* any case.
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*/
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la s8, 1f
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sub s8, s8, s7
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csrw CSR_STVEC, s8
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/* Process entries in a loop */
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.align 2
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1:
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addi s10, s10, 1
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REG_L t0, 0(s0) /* t0 = *image->entry */
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addi s0, s0, RISCV_SZPTR /* image->entry++ */
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/* IND_DESTINATION entry ? -> save destination address */
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andi t1, t0, 0x1
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beqz t1, 2f
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andi s4, t0, ~0x1
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j 1b
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2:
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/* IND_INDIRECTION entry ? -> update next entry ptr (PA) */
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andi t1, t0, 0x2
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beqz t1, 2f
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andi s0, t0, ~0x2
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addi s9, s9, 1
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csrw CSR_SATP, zero
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jalr zero, s8, 0
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2:
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/* IND_DONE entry ? -> jump to done label */
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andi t1, t0, 0x4
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beqz t1, 2f
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j 4f
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2:
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/*
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* IND_SOURCE entry ? -> copy page word by word to the
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* destination address we got from IND_DESTINATION
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*/
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andi t1, t0, 0x8
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beqz t1, 1b /* Unknown entry type, ignore it */
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andi t0, t0, ~0x8
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mv t3, s5 /* i = num words per page */
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3: /* copy loop */
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REG_L t1, (t0) /* t1 = *src_ptr */
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REG_S t1, (s4) /* *dst_ptr = *src_ptr */
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addi t0, t0, RISCV_SZPTR /* stc_ptr++ */
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addi s4, s4, RISCV_SZPTR /* dst_ptr++ */
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sub t3, t3, s6 /* i-- */
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addi s11, s11, 1 /* c++ */
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beqz t3, 1b /* copy done ? */
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j 3b
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4:
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/* Pass the arguments to the next kernel / Cleanup*/
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mv a0, s3
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mv a1, s2
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mv a2, s1
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/* Cleanup */
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mv a3, zero
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mv a4, zero
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mv a5, zero
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mv a6, zero
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mv a7, zero
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mv s0, zero
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mv s1, zero
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mv s2, zero
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mv s3, zero
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mv s4, zero
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mv s5, zero
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mv s6, zero
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mv s7, zero
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mv s8, zero
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mv s9, zero
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mv s10, zero
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mv s11, zero
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mv t0, zero
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mv t1, zero
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mv t2, zero
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mv t3, zero
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mv t4, zero
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mv t5, zero
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mv t6, zero
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csrw CSR_SEPC, zero
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csrw CSR_SCAUSE, zero
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csrw CSR_SSCRATCH, zero
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/*
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* Make sure the relocated code is visible
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* and jump to the new kernel
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*/
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fence.i
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jalr zero, a2, 0
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SYM_CODE_END(riscv_kexec_relocate)
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riscv_kexec_relocate_end:
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/* Used for jumping to crashkernel */
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.section ".text"
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SYM_CODE_START(riscv_kexec_norelocate)
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/*
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* s0: (const) Phys address to jump to
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* s1: (const) Phys address of the FDT image
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* s2: (const) The hartid of the current hart
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*/
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mv s0, a1
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mv s1, a2
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mv s2, a3
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/* Disable / cleanup interrupts */
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csrw CSR_SIE, zero
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csrw CSR_SIP, zero
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/* Pass the arguments to the next kernel / Cleanup*/
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mv a0, s2
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mv a1, s1
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mv a2, s0
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/* Cleanup */
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mv a3, zero
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mv a4, zero
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mv a5, zero
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mv a6, zero
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mv a7, zero
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mv s0, zero
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mv s1, zero
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mv s2, zero
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mv s3, zero
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mv s4, zero
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mv s5, zero
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mv s6, zero
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mv s7, zero
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mv s8, zero
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mv s9, zero
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mv s10, zero
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mv s11, zero
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mv t0, zero
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mv t1, zero
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mv t2, zero
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mv t3, zero
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mv t4, zero
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mv t5, zero
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mv t6, zero
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csrw CSR_SEPC, zero
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csrw CSR_SCAUSE, zero
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csrw CSR_SSCRATCH, zero
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/*
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* Switch to physical addressing
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* This will also trigger a jump to CSR_STVEC
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* which in this case is the address of the new
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* kernel.
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*/
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csrw CSR_STVEC, a2
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csrw CSR_SATP, zero
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SYM_CODE_END(riscv_kexec_norelocate)
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.section ".rodata"
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SYM_DATA(riscv_kexec_relocate_size,
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.long riscv_kexec_relocate_end - riscv_kexec_relocate)
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