[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] xen/riscv: introduce function for physical offset calculation
commit af670c14e87a838d8274f5b619ce57379a749d93 Author: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> AuthorDate: Thu Nov 2 10:47:58 2023 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Thu Nov 2 10:47:58 2023 +0100 xen/riscv: introduce function for physical offset calculation The function was introduced to calculate and save physical offset before MMU is enabled because access to start() is PC-relative and in case of linker_addr != load_addr it will result in incorrect value in phys_offset. Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> Acked-by: Jan Beulich <jbeulich@xxxxxxxx> --- xen/arch/riscv/include/asm/mm.h | 2 ++ xen/arch/riscv/mm.c | 21 ++++++++++++++++++--- xen/arch/riscv/riscv64/head.S | 14 ++++++++++++++ 3 files changed, 34 insertions(+), 3 deletions(-) diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h index 5e3ac5cde3..7b94cbadd7 100644 --- a/xen/arch/riscv/include/asm/mm.h +++ b/xen/arch/riscv/include/asm/mm.h @@ -15,4 +15,6 @@ void setup_initial_pagetables(void); void enable_mmu(void); void cont_after_mmu_is_enabled(void); +unsigned long calc_phys_offset(void); + #endif /* _ASM_RISCV_MM_H */ diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c index 99ed5e9623..a73f135a3c 100644 --- a/xen/arch/riscv/mm.c +++ b/xen/arch/riscv/mm.c @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0-only */ +#include <xen/cache.h> #include <xen/compiler.h> #include <xen/init.h> #include <xen/kernel.h> @@ -19,9 +20,10 @@ struct mmu_desc { pte_t *pgtbl_base; }; -#define PHYS_OFFSET ((unsigned long)_start - XEN_VIRT_START) -#define LOAD_TO_LINK(addr) ((addr) - PHYS_OFFSET) -#define LINK_TO_LOAD(addr) ((addr) + PHYS_OFFSET) +static unsigned long __ro_after_init phys_offset; + +#define LOAD_TO_LINK(addr) ((unsigned long)(addr) - phys_offset) +#define LINK_TO_LOAD(addr) ((unsigned long)(addr) + phys_offset) /* * It is expected that Xen won't be more then 2 MB. @@ -273,3 +275,16 @@ void __init noreturn noinline enable_mmu() switch_stack_and_jump((unsigned long)cpu0_boot_stack + STACK_SIZE, cont_after_mmu_is_enabled); } + +/* + * calc_phys_offset() should be used before MMU is enabled because access to + * start() is PC-relative and in case when load_addr != linker_addr phys_offset + * will have an incorrect value + */ +unsigned long __init calc_phys_offset(void) +{ + volatile unsigned long load_start = (unsigned long)_start; + + phys_offset = load_start - XEN_VIRT_START; + return phys_offset; +} diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S index 2c0304646a..ae194bb099 100644 --- a/xen/arch/riscv/riscv64/head.S +++ b/xen/arch/riscv/riscv64/head.S @@ -29,6 +29,20 @@ ENTRY(start) jal reset_stack + /* + * save hart_id ( bootcpu_id ) and dtb_base as a0 and a1 register can + * be used by C code + */ + mv s0, a0 + mv s1, a1 + + jal calc_phys_offset + mv s2, a0 + + /* restore hart_id ( bootcpu_id ) and dtb address */ + mv a0, s0 + mv a1, s1 + tail start_xen .section .text, "ax", %progbits -- generated by git-patchbot for /home/xen/git/xen.git#master
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