/* SPDX-License-Identifier: GPL-2.0-only *//* * Copyright (C) 2012 Regents of the University of California */ #include <asm/asm-offsets.h>#include <asm/asm.h>#include <linux/init.h>#include <linux/linkage.h>#include <asm/thread_info.h>#include <asm/page.h>#include <asm/pgtable.h>#include <asm/csr.h>#include <asm/hwcap.h>#include <asm/image.h>#include <asm/scs.h>#include <asm/usercfi.h>#include "efi-header.S" __HEADSYM_CODE_START(_start)	/*	 * Image header expected by Linux boot-loaders. The image header data	 * structure is described in asm/image.h.	 * Do not modify it without modifying the structure and all bootloaders	 * that expects this header format!!	 */#ifdef CONFIG_EFI	/*	 * This instruction decodes to "MZ" ASCII required by UEFI.	 */	c.li s4,-13	j _start_kernel#else	/* jump to start kernel */	j _start_kernel	/* reserved */	.word 0#endif	.balign 8#ifdef CONFIG_RISCV_M_MODE	/* Image load offset (0MB) from start of RAM for M-mode */	.dword 0#else#if __riscv_xlen == 64	/* Image load offset(2MB) from start of RAM */	.dword 0x200000#else	/* Image load offset(4MB) from start of RAM */	.dword 0x400000#endif#endif	/* Effective size of kernel image */	.dword _end - _start	.dword __HEAD_FLAGS	.word RISCV_HEADER_VERSION	.word 0	.dword 0	.ascii RISCV_IMAGE_MAGIC	.balign 4	.ascii RISCV_IMAGE_MAGIC2#ifdef CONFIG_EFI	.word pe_head_start - _startpe_head_start: 	__EFI_PE_HEADER#else	.word 0#endif .align 2#ifdef CONFIG_MMU	.global relocate_enable_mmurelocate_enable_mmu:	/* Relocate return address */	la a1, kernel_map	REG_L a1, KERNEL_MAP_VIRT_ADDR(a1)	la a2, _start	sub a1, a1, a2	add ra, ra, a1 	/* Point stvec to virtual address of instruction after satp write */	la a2, 1f	add a2, a2, a1	csrw CSR_TVEC, a2 	/* Compute satp for kernel page tables, but don't load it yet */	srl a2, a0, PAGE_SHIFT	la a1, satp_mode	REG_L a1, 0(a1)	or a2, a2, a1 	/*	 * Load trampoline page directory, which will cause us to trap to	 * stvec if VA != PA, or simply fall through if VA == PA.  We need a	 * full fence here because setup_vm() just wrote these PTEs and we need	 * to ensure the new translations are in use.	 */	la a0, trampoline_pg_dir	srl a0, a0, PAGE_SHIFT	or a0, a0, a1	sfence.vma	csrw CSR_SATP, a0.align 21:	/* Set trap vector to spin forever to help debug */	la a0, .Lsecondary_park	csrw CSR_TVEC, a0 	/* Reload the global pointer */	load_global_pointer 	/*	 * Switch to kernel page tables.  A full fence is necessary in order to	 * avoid using the trampoline translations, which are only correct for	 * the first superpage.  Fetching the fence is guaranteed to work	 * because that first superpage is translated the same way.	 */	csrw CSR_SATP, a2	sfence.vma 	ret#endif /* CONFIG_MMU */#ifdef CONFIG_SMP	.global secondary_start_sbisecondary_start_sbi:	/* Mask all interrupts */	csrw CSR_IE, zero	csrw CSR_IP, zero #ifndef CONFIG_RISCV_M_MODE	/* Enable time CSR */	li t0, 0x2	csrw CSR_SCOUNTEREN, t0#endif 	/* Load the global pointer */	load_global_pointer 	/*	 * Disable FPU & VECTOR to detect illegal usage of	 * floating point or vector in kernel space	 */	li t0, SR_FS_VS	csrc CSR_STATUS, t0 	/* Set trap vector to spin forever to help debug */	la a3, .Lsecondary_park	csrw CSR_TVEC, a3 	/* a0 contains the hartid & a1 contains boot data */	li a2, SBI_HART_BOOT_TASK_PTR_OFFSET	add a2, a2, a1	REG_L tp, (a2)	li a3, SBI_HART_BOOT_STACK_PTR_OFFSET	add a3, a3, a1	REG_L sp, (a3) .Lsecondary_start_common: #ifdef CONFIG_MMU	/* Enable virtual memory and relocate to virtual address */	la a0, swapper_pg_dir	call relocate_enable_mmu#endif	call .Lsetup_trap_vector#if defined(CONFIG_RISCV_SBI) && defined(CONFIG_RISCV_USER_CFI)	li a7, SBI_EXT_FWFT	li a6, SBI_EXT_FWFT_SET	li a0, SBI_FWFT_SHADOW_STACK	li a1, 1 /* enable supervisor to access shadow stack access */	li a2, SBI_FWFT_SET_FLAG_LOCK	ecall	beqz a0, 1f	la a1, riscv_nousercfi	li a0, CMDLINE_DISABLE_RISCV_USERCFI_BCFI	REG_S a0, (a1)1:#endif	scs_load_current	call smp_callin#endif /* CONFIG_SMP */ .align 2.Lsecondary_park:	/*	 * Park this hart if we:	 *  - have too many harts on CONFIG_RISCV_BOOT_SPINWAIT	 *  - receive an early trap, before setup_trap_vector finished	 *  - fail in smp_callin(), as a successful one wouldn't return	 */	wfi	j .Lsecondary_park .align 2.Lsetup_trap_vector:	/* Set trap vector to exception handler */	la a0, handle_exception	csrw CSR_TVEC, a0 	/*	 * Set sup0 scratch register to 0, indicating to exception vector that	 * we are presently executing in kernel.	 */	csrw CSR_SCRATCH, zero	ret SYM_CODE_END(_start) SYM_CODE_START(_start_kernel)	/* Mask all interrupts */	csrw CSR_IE, zero	csrw CSR_IP, zero #ifdef CONFIG_RISCV_M_MODE	/* flush the instruction cache */	fence.i 	/* Reset all registers except ra, a0, a1 */	call reset_regs 	/*	 * Setup a PMP to permit access to all of memory.  Some machines may	 * not implement PMPs, so we set up a quick trap handler to just skip	 * touching the PMPs on any trap.	 */	la a0, .Lpmp_done	csrw CSR_TVEC, a0 	li a0, -1	csrw CSR_PMPADDR0, a0	li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X)	csrw CSR_PMPCFG0, a0.align 2.Lpmp_done: 	/*	 * The hartid in a0 is expected later on, and we have no firmware	 * to hand it to us.	 */	csrr a0, CSR_MHARTID#else	/* Enable time CSR */	li t0, 0x2	csrw CSR_SCOUNTEREN, t0#endif /* CONFIG_RISCV_M_MODE */ 	/* Load the global pointer */	load_global_pointer 	/*	 * Disable FPU & VECTOR to detect illegal usage of	 * floating point or vector in kernel space	 */	li t0, SR_FS_VS	csrc CSR_STATUS, t0 #ifdef CONFIG_RISCV_BOOT_SPINWAIT	li t0, CONFIG_NR_CPUS	blt a0, t0, .Lgood_cores	tail .Lsecondary_park.Lgood_cores: 	/* The lottery system is only required for spinwait booting method */	/* Pick one hart to run the main boot sequence */	la a3, hart_lottery	li a2, 1	amoadd.w a3, a2, (a3)	bnez a3, .Lsecondary_start#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ 	/* Clear BSS for flat non-ELF images */	la a3, __bss_start	la a4, __bss_stop	ble a4, a3, .Lclear_bss_done.Lclear_bss:	REG_S zero, (a3)	add a3, a3, RISCV_SZPTR	blt a3, a4, .Lclear_bss.Lclear_bss_done:	la a2, boot_cpu_hartid	REG_S a0, (a2) 	/* Initialize page tables and relocate to virtual addresses */	la tp, init_task	la sp, init_thread_union + THREAD_SIZE	addi sp, sp, -PT_SIZE_ON_STACK	scs_load_init_stack#ifdef CONFIG_BUILTIN_DTB	la a0, __dtb_start#else	mv a0, a1#endif /* CONFIG_BUILTIN_DTB */	/* Set trap vector to spin forever to help debug */	la a3, .Lsecondary_park	csrw CSR_TVEC, a3	call setup_vm#ifdef CONFIG_MMU	la a0, early_pg_dir	call relocate_enable_mmu#endif /* CONFIG_MMU */ 	call .Lsetup_trap_vector	/* Restore C environment */	la tp, init_task	la sp, init_thread_union + THREAD_SIZE	addi sp, sp, -PT_SIZE_ON_STACK#if defined(CONFIG_RISCV_SBI) && defined(CONFIG_RISCV_USER_CFI)	li a7, SBI_EXT_FWFT	li a6, SBI_EXT_FWFT_SET	li a0, SBI_FWFT_SHADOW_STACK	li a1, 1 /* enable supervisor to access shadow stack access */	li a2, SBI_FWFT_SET_FLAG_LOCK	ecall	beqz a0, 1f	la a1, riscv_nousercfi	li a0, CMDLINE_DISABLE_RISCV_USERCFI_BCFI	REG_S a0, (a1)1:#endif	scs_load_current #ifdef CONFIG_KASAN	call kasan_early_init#endif	/* Start the kernel */	call soc_early_init	tail start_kernel #ifdef CONFIG_RISCV_BOOT_SPINWAIT.Lsecondary_start:	/* Set trap vector to spin forever to help debug */	la a3, .Lsecondary_park	csrw CSR_TVEC, a3 	slli a3, a0, LGREG	la a1, __cpu_spinwait_stack_pointer	la a2, __cpu_spinwait_task_pointer	add a1, a3, a1	add a2, a3, a2 	/*	 * This hart didn't win the lottery, so we wait for the winning hart to	 * get far enough along the boot process that it should continue.	 */.Lwait_for_cpu_up:	/* FIXME: We should WFI to save some energy here. */	REG_L sp, (a1)	REG_L tp, (a2)	beqz sp, .Lwait_for_cpu_up	beqz tp, .Lwait_for_cpu_up	fence 	tail .Lsecondary_start_common#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ SYM_CODE_END(_start_kernel) #ifdef CONFIG_RISCV_M_MODESYM_CODE_START_LOCAL(reset_regs)	li	sp, 0	li	gp, 0	li	tp, 0	li	t0, 0	li	t1, 0	li	t2, 0	li	s0, 0	li	s1, 0	li	a2, 0	li	a3, 0	li	a4, 0	li	a5, 0	li	a6, 0	li	a7, 0	li	s2, 0	li	s3, 0	li	s4, 0	li	s5, 0	li	s6, 0	li	s7, 0	li	s8, 0	li	s9, 0	li	s10, 0	li	s11, 0	li	t3, 0	li	t4, 0	li	t5, 0	li	t6, 0	csrw	CSR_SCRATCH, 0 #ifdef CONFIG_FPU	csrr	t0, CSR_MISA	andi	t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D)	beqz	t0, .Lreset_regs_done_fpu 	li	t1, SR_FS	csrs	CSR_STATUS, t1	fmv.s.x	f0, zero	fmv.s.x	f1, zero	fmv.s.x	f2, zero	fmv.s.x	f3, zero	fmv.s.x	f4, zero	fmv.s.x	f5, zero	fmv.s.x	f6, zero	fmv.s.x	f7, zero	fmv.s.x	f8, zero	fmv.s.x	f9, zero	fmv.s.x	f10, zero	fmv.s.x	f11, zero	fmv.s.x	f12, zero	fmv.s.x	f13, zero	fmv.s.x	f14, zero	fmv.s.x	f15, zero	fmv.s.x	f16, zero	fmv.s.x	f17, zero	fmv.s.x	f18, zero	fmv.s.x	f19, zero	fmv.s.x	f20, zero	fmv.s.x	f21, zero	fmv.s.x	f22, zero	fmv.s.x	f23, zero	fmv.s.x	f24, zero	fmv.s.x	f25, zero	fmv.s.x	f26, zero	fmv.s.x	f27, zero	fmv.s.x	f28, zero	fmv.s.x	f29, zero	fmv.s.x	f30, zero	fmv.s.x	f31, zero	csrw	fcsr, 0	/* note that the caller must clear SR_FS */.Lreset_regs_done_fpu:#endif /* CONFIG_FPU */ #ifdef CONFIG_RISCV_ISA_V	csrr	t0, CSR_MISA	li	t1, COMPAT_HWCAP_ISA_V	and	t0, t0, t1	beqz	t0, .Lreset_regs_done_vector 	/*	 * Clear vector registers and reset vcsr	 * VLMAX has a defined value, VLEN is a constant,	 * and this form of vsetvli is defined to set vl to VLMAX.	 */	li	t1, SR_VS	csrs	CSR_STATUS, t1	csrs	CSR_VCSR, x0	vsetvli t1, x0, e8, m8, ta, ma	vmv.v.i v0, 0	vmv.v.i v8, 0	vmv.v.i v16, 0	vmv.v.i v24, 0	/* note that the caller must clear SR_VS */.Lreset_regs_done_vector:#endif /* CONFIG_RISCV_ISA_V */	retSYM_CODE_END(reset_regs)#endif /* CONFIG_RISCV_M_MODE */