riscv/cstart.S - kvm-unit-tests - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Boot entry point and assembler functions for riscv.
  *
  * Copyright (C) 2023, Ventana Micro Systems Inc., Andrew Jones <ajones@ventanamicro.com>
  */
 #include <asm/asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/csr.h>


 .macro push_fp, ra=ra
 	addi	sp, sp, -FP_SIZE
 	REG_S	\ra, (FP_SIZE - SZREG)(sp)
 	REG_S	fp, (FP_SIZE - 2*SZREG)(sp)
 	addi	fp, sp, FP_SIZE
 .endm

 .macro pop_fp
 	REG_L	ra, (FP_SIZE - SZREG)(sp)
 	REG_L	fp, (FP_SIZE - 2*SZREG)(sp)
 	addi	sp, sp, FP_SIZE
 .endm

 .macro zero_range, tmp1, tmp2
 9998:	beq	\tmp1, \tmp2, 9997f
 	REG_S	zero, 0(\tmp1)
 	addi	\tmp1, \tmp1, 8
 	j	9998b
 9997:
 .endm

 #ifdef CONFIG_EFI
 #include "efi/crt0-efi-riscv64.S"
 #else
 	.section .init

 /*
  * The hartid of the current core is in a0
  * The address of the devicetree is in a1
  *
  * See Linux kernel doc Documentation/riscv/boot.rst
  */
 .global start
 start:
 	/*
 	 * Stash the hartid in scratch and shift the dtb address into a0.
 	 * thread_info_init() will later promote scratch to point at thread
 	 * local storage.
 	 */
 	csrw	CSR_SSCRATCH, a0
 	mv	a0, a1

 	/*
 	 * Update all R_RISCV_RELATIVE relocations using the table
 	 * of Elf32_Rela/Elf64_Rela entries between reloc_start/end.
 	 * The build will not emit other relocation types.
 	 */
 	la	a1, reloc_start
 	la	a2, reloc_end
 	la	a3, start			// base
 1:
 	bge	a1, a2, 1f
 	REG_L	a4, ELF_RELA_OFFSET(a1)		// r_offset
 	REG_L	a5, ELF_RELA_ADDEND(a1)		// r_addend
 	add	a4, a3, a4			// addr = base + r_offset
 	add	a5, a3, a5			// val = base + r_addend
 	REG_S	a5, 0(a4)			// *addr = val
 	addi	a1, a1, ELF_RELA_SIZE
 	j	1b

 1:
 	/* zero BSS */
 	la	a1, bss
 	la	a2, ebss
 	zero_range a1, a2

 	/* zero and set up stack */
 	la	sp, stacktop
 	li	a1, -8192
 	add	a1, sp, a1
 	zero_range a1, sp
 	mv	fp, zero			// Ensure fp starts out as zero

 	/* set up exception handling */
 	la	a1, exception_vectors
 	csrw	CSR_STVEC, a1

 	/* complete setup */
 	la	a1, stacktop			// a1 is the base of free memory
 	mv	a2, zero			// clear a2 for xlen=32
 	call	setup				// a0 is the addr of the dtb

 	/* run the test */
 	la	a0, __argc
 	lw	a0, 0(a0)
 	la	a1, __argv
 	la	a2, __environ
 	call	main
 	call	exit
 	j	halt

 #endif /* !CONFIG_EFI */
 	.text

 .balign 4
 .global halt
 halt:
 1:	wfi
 	j	1b

 /*
  * hartid_to_cpu
  *   a0 is a hartid on entry
  * Returns, in a0, the corresponding cpuid, or -1 if no
  * thread_info struct with 'hartid' is found.
  */
 .balign 4
 .global hartid_to_cpu
 hartid_to_cpu:
 	la	t0, cpus
 	la	t1, nr_cpus
 	lw	t1, 0(t1)
 	li	t2, 0
 1:	bne	t2, t1, 2f
 	li	a0, -1
 	ret
 2:	REG_L	t3, THREAD_INFO_HARTID(t0)
 	bne	a0, t3, 3f
 	lw	a0, THREAD_INFO_CPU(t0)
 	ret
 3:	addi	t0, t0, THREAD_INFO_SIZE
 	addi	t2, t2, 1
 	j	1b

 .balign 4
 .global secondary_entry
 secondary_entry:
 	/*
 	 * From the "HSM Hart Start Register State" table of the SBI spec:
 	 *	satp		0
 	 *	sstatus.SIE	0
 	 *	a0		hartid
 	 *	a1		opaque parameter
 	 *
 	 * __smp_boot_secondary() sets the opaque parameter (a1) to the physical
 	 * address of the stack and the stack contains the secondary data.
 	 */
 	csrw	CSR_SSCRATCH, a0
 	mv	sp, a1
 	mv	fp, zero
 	addi	sp, sp, -SECONDARY_DATA_SIZE
 	REG_L	a0, SECONDARY_STVEC(sp)
 	csrw	CSR_STVEC, a0
 	mv	a0, sp
 	call	secondary_cinit
 	addi	sp, sp, SECONDARY_DATA_SIZE
 	jalr	ra, a0
 	call	do_idle
 	j	.	/* unreachable */

 /*
  * Save context to address in a0.
  * For a0, sets PT_A0(a0) to the contents of PT_ORIG_A0(a0).
  * Clobbers a1.
  */
 .macro save_context
 	REG_S	ra, PT_RA(a0)			// x1
 	REG_S	sp, PT_SP(a0)			// x2
 	REG_S	gp, PT_GP(a0)			// x3
 	REG_S	tp, PT_TP(a0)			// x4
 	REG_S	t0, PT_T0(a0)			// x5
 	REG_S	t1, PT_T1(a0)			// x6
 	REG_S	t2, PT_T2(a0)			// x7
 	REG_S	s0, PT_S0(a0)			// x8 / fp
 	REG_S	s1, PT_S1(a0)			// x9
 	/* a0 */				// x10
 	REG_S   a1, PT_A1(a0)			// x11
 	REG_S	a2, PT_A2(a0)			// x12
 	REG_S	a3, PT_A3(a0)			// x13
 	REG_S	a4, PT_A4(a0)			// x14
 	REG_S	a5, PT_A5(a0)			// x15
 	REG_S	a6, PT_A6(a0)			// x16
 	REG_S	a7, PT_A7(a0)			// x17
 	REG_S	s2, PT_S2(a0)			// x18
 	REG_S	s3, PT_S3(a0)			// x19
 	REG_S	s4, PT_S4(a0)			// x20
 	REG_S	s5, PT_S5(a0)			// x21
 	REG_S	s6, PT_S6(a0)			// x22
 	REG_S	s7, PT_S7(a0)			// x23
 	REG_S	s8, PT_S8(a0)			// x24
 	REG_S	s9, PT_S9(a0)			// x25
 	REG_S	s10, PT_S10(a0)			// x26
 	REG_S	s11, PT_S11(a0)			// x27
 	REG_S	t3, PT_T3(a0)			// x28
 	REG_S	t4, PT_T4(a0)			// x29
 	REG_S	t5, PT_T5(a0)			// x30
 	REG_S	t6, PT_T6(a0)			// x31
 	csrr	a1, CSR_SEPC
 	REG_S	a1, PT_EPC(a0)
 	csrr	a1, CSR_SSTATUS
 	REG_S	a1, PT_STATUS(a0)
 	csrr	a1, CSR_STVAL
 	REG_S	a1, PT_BADADDR(a0)
 	csrr	a1, CSR_SCAUSE
 	REG_S	a1, PT_CAUSE(a0)
 	REG_L	a1, PT_ORIG_A0(a0)
 	REG_S	a1, PT_A0(a0)
 .endm

 /*
  * Restore context from address in a0.
  * Also restores a0.
  */
 .macro restore_context
 	REG_L	ra, PT_RA(a0)			// x1
 	REG_L	sp, PT_SP(a0)			// x2
 	REG_L	gp, PT_GP(a0)			// x3
 	REG_L	tp, PT_TP(a0)			// x4
 	REG_L	t0, PT_T0(a0)			// x5
 	REG_L	t1, PT_T1(a0)			// x6
 	REG_L	t2, PT_T2(a0)			// x7
 	REG_L	s0, PT_S0(a0)			// x8 / fp
 	REG_L	s1, PT_S1(a0)			// x9
 	/* a0 */				// x10
 	/* a1 */				// x11
 	REG_L	a2, PT_A2(a0)			// x12
 	REG_L	a3, PT_A3(a0)			// x13
 	REG_L	a4, PT_A4(a0)			// x14
 	REG_L	a5, PT_A5(a0)			// x15
 	REG_L	a6, PT_A6(a0)			// x16
 	REG_L	a7, PT_A7(a0)			// x17
 	REG_L	s2, PT_S2(a0)			// x18
 	REG_L	s3, PT_S3(a0)			// x19
 	REG_L	s4, PT_S4(a0)			// x20
 	REG_L	s5, PT_S5(a0)			// x21
 	REG_L	s6, PT_S6(a0)			// x22
 	REG_L	s7, PT_S7(a0)			// x23
 	REG_L	s8, PT_S8(a0)			// x24
 	REG_L	s9, PT_S9(a0)			// x25
 	REG_L	s10, PT_S10(a0)			// x26
 	REG_L	s11, PT_S11(a0)			// x27
 	REG_L	t3, PT_T3(a0)			// x28
 	REG_L	t4, PT_T4(a0)			// x29
 	REG_L	t5, PT_T5(a0)			// x30
 	REG_L	t6, PT_T6(a0)			// x31
 	REG_L	a1, PT_EPC(a0)
 	csrw	CSR_SEPC, a1
 	REG_L	a1, PT_STATUS(a0)
 	csrw	CSR_SSTATUS, a1
 	REG_L	a1, PT_BADADDR(a0)
 	csrw	CSR_STVAL, a1
 	REG_L	a1, PT_CAUSE(a0)
 	csrw	CSR_SCAUSE, a1
 	REG_L	a1, PT_A1(a0)
 	REG_L	a0, PT_A0(a0)
 .endm

 .balign 4
 .global exception_vectors
 exception_vectors:
 	REG_S	a0, (-PT_SIZE - FP_SIZE + PT_ORIG_A0)(sp)
 	addi	a0, sp, -PT_SIZE - FP_SIZE
 	save_context
 	/*
 	 * Set a frame pointer "ra" which points to the last instruction.
 	 * Add 1 to it, because pretty_print_stacks.py subtracts 1.
 	 */
 	REG_L	a1, PT_EPC(a0)
 	addi	a1, a1, 1
 	push_fp	a1
 	mv	sp, a0
 	call	do_handle_exception
 	mv	a0, sp
 	restore_context
 	sret
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* Boot entry point and assembler functions for riscv.
	*
	* Copyright (C) 2023, Ventana Micro Systems Inc., Andrew Jones <ajones@ventanamicro.com>
	*/
	#include <asm/asm.h>
	#include <asm/asm-offsets.h>
	#include <asm/csr.h>


	.macro push_fp, ra=ra
	addi sp, sp, -FP_SIZE
	REG_S \ra, (FP_SIZE - SZREG)(sp)
	REG_S fp, (FP_SIZE - 2*SZREG)(sp)
	addi fp, sp, FP_SIZE
	.endm

	.macro pop_fp
	REG_L ra, (FP_SIZE - SZREG)(sp)
	REG_L fp, (FP_SIZE - 2*SZREG)(sp)
	addi sp, sp, FP_SIZE
	.endm

	.macro zero_range, tmp1, tmp2
	9998: beq \tmp1, \tmp2, 9997f
	REG_S zero, 0(\tmp1)
	addi \tmp1, \tmp1, 8
	j 9998b
	9997:
	.endm

	#ifdef CONFIG_EFI
	#include "efi/crt0-efi-riscv64.S"
	#else
	.section .init

	/*
	* The hartid of the current core is in a0
	* The address of the devicetree is in a1
	*
	* See Linux kernel doc Documentation/riscv/boot.rst
	*/
	.global start
	start:
	/*
	* Stash the hartid in scratch and shift the dtb address into a0.
	* thread_info_init() will later promote scratch to point at thread
	* local storage.
	*/
	csrw CSR_SSCRATCH, a0
	mv a0, a1

	/*
	* Update all R_RISCV_RELATIVE relocations using the table
	* of Elf32_Rela/Elf64_Rela entries between reloc_start/end.
	* The build will not emit other relocation types.
	*/
	la a1, reloc_start
	la a2, reloc_end
	la a3, start // base
	1:
	bge a1, a2, 1f
	REG_L a4, ELF_RELA_OFFSET(a1) // r_offset
	REG_L a5, ELF_RELA_ADDEND(a1) // r_addend
	add a4, a3, a4 // addr = base + r_offset
	add a5, a3, a5 // val = base + r_addend
	REG_S a5, 0(a4) // *addr = val
	addi a1, a1, ELF_RELA_SIZE
	j 1b

	1:
	/* zero BSS */
	la a1, bss
	la a2, ebss
	zero_range a1, a2

	/* zero and set up stack */
	la sp, stacktop
	li a1, -8192
	add a1, sp, a1
	zero_range a1, sp
	mv fp, zero // Ensure fp starts out as zero

	/* set up exception handling */
	la a1, exception_vectors
	csrw CSR_STVEC, a1

	/* complete setup */
	la a1, stacktop // a1 is the base of free memory
	mv a2, zero // clear a2 for xlen=32
	call setup // a0 is the addr of the dtb

	/* run the test */
	la a0, __argc
	lw a0, 0(a0)
	la a1, __argv
	la a2, __environ
	call main
	call exit
	j halt

	#endif /* !CONFIG_EFI */
	.text

	.balign 4
	.global halt
	halt:
	1: wfi
	j 1b

	/*
	* hartid_to_cpu
	* a0 is a hartid on entry
	* Returns, in a0, the corresponding cpuid, or -1 if no
	* thread_info struct with 'hartid' is found.
	*/
	.balign 4
	.global hartid_to_cpu
	hartid_to_cpu:
	la t0, cpus
	la t1, nr_cpus
	lw t1, 0(t1)
	li t2, 0
	1: bne t2, t1, 2f
	li a0, -1
	ret
	2: REG_L t3, THREAD_INFO_HARTID(t0)
	bne a0, t3, 3f
	lw a0, THREAD_INFO_CPU(t0)
	ret
	3: addi t0, t0, THREAD_INFO_SIZE
	addi t2, t2, 1
	j 1b

	.balign 4
	.global secondary_entry
	secondary_entry:
	/*
	* From the "HSM Hart Start Register State" table of the SBI spec:
	* satp 0
	* sstatus.SIE 0
	* a0 hartid
	* a1 opaque parameter
	*
	* __smp_boot_secondary() sets the opaque parameter (a1) to the physical
	* address of the stack and the stack contains the secondary data.
	*/
	csrw CSR_SSCRATCH, a0
	mv sp, a1
	mv fp, zero
	addi sp, sp, -SECONDARY_DATA_SIZE
	REG_L a0, SECONDARY_STVEC(sp)
	csrw CSR_STVEC, a0
	mv a0, sp
	call secondary_cinit
	addi sp, sp, SECONDARY_DATA_SIZE
	jalr ra, a0
	call do_idle
	j . /* unreachable */

	/*
	* Save context to address in a0.
	* For a0, sets PT_A0(a0) to the contents of PT_ORIG_A0(a0).
	* Clobbers a1.
	*/
	.macro save_context
	REG_S ra, PT_RA(a0) // x1
	REG_S sp, PT_SP(a0) // x2
	REG_S gp, PT_GP(a0) // x3
	REG_S tp, PT_TP(a0) // x4
	REG_S t0, PT_T0(a0) // x5
	REG_S t1, PT_T1(a0) // x6
	REG_S t2, PT_T2(a0) // x7
	REG_S s0, PT_S0(a0) // x8 / fp
	REG_S s1, PT_S1(a0) // x9
	/* a0 */ // x10
	REG_S a1, PT_A1(a0) // x11
	REG_S a2, PT_A2(a0) // x12
	REG_S a3, PT_A3(a0) // x13
	REG_S a4, PT_A4(a0) // x14
	REG_S a5, PT_A5(a0) // x15
	REG_S a6, PT_A6(a0) // x16
	REG_S a7, PT_A7(a0) // x17
	REG_S s2, PT_S2(a0) // x18
	REG_S s3, PT_S3(a0) // x19
	REG_S s4, PT_S4(a0) // x20
	REG_S s5, PT_S5(a0) // x21
	REG_S s6, PT_S6(a0) // x22
	REG_S s7, PT_S7(a0) // x23
	REG_S s8, PT_S8(a0) // x24
	REG_S s9, PT_S9(a0) // x25
	REG_S s10, PT_S10(a0) // x26
	REG_S s11, PT_S11(a0) // x27
	REG_S t3, PT_T3(a0) // x28
	REG_S t4, PT_T4(a0) // x29
	REG_S t5, PT_T5(a0) // x30
	REG_S t6, PT_T6(a0) // x31
	csrr a1, CSR_SEPC
	REG_S a1, PT_EPC(a0)
	csrr a1, CSR_SSTATUS
	REG_S a1, PT_STATUS(a0)
	csrr a1, CSR_STVAL
	REG_S a1, PT_BADADDR(a0)
	csrr a1, CSR_SCAUSE
	REG_S a1, PT_CAUSE(a0)
	REG_L a1, PT_ORIG_A0(a0)
	REG_S a1, PT_A0(a0)
	.endm

	/*
	* Restore context from address in a0.
	* Also restores a0.
	*/
	.macro restore_context
	REG_L ra, PT_RA(a0) // x1
	REG_L sp, PT_SP(a0) // x2
	REG_L gp, PT_GP(a0) // x3
	REG_L tp, PT_TP(a0) // x4
	REG_L t0, PT_T0(a0) // x5
	REG_L t1, PT_T1(a0) // x6
	REG_L t2, PT_T2(a0) // x7
	REG_L s0, PT_S0(a0) // x8 / fp
	REG_L s1, PT_S1(a0) // x9
	/* a0 */ // x10
	/* a1 */ // x11
	REG_L a2, PT_A2(a0) // x12
	REG_L a3, PT_A3(a0) // x13
	REG_L a4, PT_A4(a0) // x14
	REG_L a5, PT_A5(a0) // x15
	REG_L a6, PT_A6(a0) // x16
	REG_L a7, PT_A7(a0) // x17
	REG_L s2, PT_S2(a0) // x18
	REG_L s3, PT_S3(a0) // x19
	REG_L s4, PT_S4(a0) // x20
	REG_L s5, PT_S5(a0) // x21
	REG_L s6, PT_S6(a0) // x22
	REG_L s7, PT_S7(a0) // x23
	REG_L s8, PT_S8(a0) // x24
	REG_L s9, PT_S9(a0) // x25
	REG_L s10, PT_S10(a0) // x26
	REG_L s11, PT_S11(a0) // x27
	REG_L t3, PT_T3(a0) // x28
	REG_L t4, PT_T4(a0) // x29
	REG_L t5, PT_T5(a0) // x30
	REG_L t6, PT_T6(a0) // x31
	REG_L a1, PT_EPC(a0)
	csrw CSR_SEPC, a1
	REG_L a1, PT_STATUS(a0)
	csrw CSR_SSTATUS, a1
	REG_L a1, PT_BADADDR(a0)
	csrw CSR_STVAL, a1
	REG_L a1, PT_CAUSE(a0)
	csrw CSR_SCAUSE, a1
	REG_L a1, PT_A1(a0)
	REG_L a0, PT_A0(a0)
	.endm

	.balign 4
	.global exception_vectors
	exception_vectors:
	REG_S a0, (-PT_SIZE - FP_SIZE + PT_ORIG_A0)(sp)
	addi a0, sp, -PT_SIZE - FP_SIZE
	save_context
	/*
	* Set a frame pointer "ra" which points to the last instruction.
	* Add 1 to it, because pretty_print_stacks.py subtracts 1.
	*/
	REG_L a1, PT_EPC(a0)
	addi a1, a1, 1
	push_fp a1
	mv sp, a0
	call do_handle_exception
	mv a0, sp
	restore_context
	sret