diff options
| -rw-r--r-- | arch/riscv/include/asm/asm.h | 1 | ||||
| -rw-r--r-- | arch/riscv/kernel/entry.S | 21 | ||||
| -rw-r--r-- | arch/riscv/mm/init.c | 12 |
3 files changed, 32 insertions, 2 deletions
diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h index 5a02b7d50940..9c992a88d858 100644 --- a/arch/riscv/include/asm/asm.h +++ b/arch/riscv/include/asm/asm.h @@ -22,6 +22,7 @@ #define REG_L __REG_SEL(ld, lw) #define REG_S __REG_SEL(sd, sw) +#define REG_SC __REG_SEL(sc.d, sc.w) #define SZREG __REG_SEL(8, 4) #define LGREG __REG_SEL(3, 2) diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index da7aa88113c2..2d592da1e776 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -98,7 +98,26 @@ _save_context: */ .macro RESTORE_ALL REG_L a0, PT_SSTATUS(sp) - REG_L a2, PT_SEPC(sp) + /* + * The current load reservation is effectively part of the processor's + * state, in the sense that load reservations cannot be shared between + * different hart contexts. We can't actually save and restore a load + * reservation, so instead here we clear any existing reservation -- + * it's always legal for implementations to clear load reservations at + * any point (as long as the forward progress guarantee is kept, but + * we'll ignore that here). + * + * Dangling load reservations can be the result of taking a trap in the + * middle of an LR/SC sequence, but can also be the result of a taken + * forward branch around an SC -- which is how we implement CAS. As a + * result we need to clear reservations between the last CAS and the + * jump back to the new context. While it is unlikely the store + * completes, implementations are allowed to expand reservations to be + * arbitrarily large. + */ + REG_L a2, PT_SEPC(sp) + REG_SC x0, a2, PT_SEPC(sp) + csrw CSR_SSTATUS, a0 csrw CSR_SEPC, a2 diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index f0ba71304b6e..83f7d12042fb 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -11,6 +11,7 @@ #include <linux/swap.h> #include <linux/sizes.h> #include <linux/of_fdt.h> +#include <linux/libfdt.h> #include <asm/fixmap.h> #include <asm/tlbflush.h> @@ -82,6 +83,8 @@ disable: } #endif /* CONFIG_BLK_DEV_INITRD */ +static phys_addr_t dtb_early_pa __initdata; + void __init setup_bootmem(void) { struct memblock_region *reg; @@ -117,7 +120,12 @@ void __init setup_bootmem(void) setup_initrd(); #endif /* CONFIG_BLK_DEV_INITRD */ - early_init_fdt_reserve_self(); + /* + * Avoid using early_init_fdt_reserve_self() since __pa() does + * not work for DTB pointers that are fixmap addresses + */ + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); + early_init_fdt_scan_reserved_mem(); memblock_allow_resize(); memblock_dump_all(); @@ -393,6 +401,8 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) /* Save pointer to DTB for early FDT parsing */ dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK); + /* Save physical address for memblock reservation */ + dtb_early_pa = dtb_pa; } static void __init setup_vm_final(void) |