From e8a62cc26ddf53a3c6ba2a8d33036cf7b84f3923 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Mon, 6 Dec 2021 11:46:51 +0100 Subject: riscv: Implement sv48 support By adding a new 4th level of page table, give the possibility to 64bit kernel to address 2^48 bytes of virtual address: in practice, that offers 128TB of virtual address space to userspace and allows up to 64TB of physical memory. If the underlying hardware does not support sv48, we will automatically fallback to a standard 3-level page table by folding the new PUD level into PGDIR level. In order to detect HW capabilities at runtime, we use SATP feature that ignores writes with an unsupported mode. Signed-off-by: Alexandre Ghiti Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/head.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/riscv/kernel') diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index f52f01ecbeea..10e718559960 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -105,7 +105,8 @@ relocate: /* Compute satp for kernel page tables, but don't load it yet */ srl a2, a0, PAGE_SHIFT - li a1, SATP_MODE + la a1, satp_mode + REG_L a1, 0(a1) or a2, a2, a1 /* -- cgit v1.2.3 From 73c7c8f68e7266bd558227bd9c598cb90b1673cc Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Mon, 6 Dec 2021 11:46:52 +0100 Subject: riscv: Use pgtable_l4_enabled to output mmu_type in cpuinfo Now that the mmu type is determined at runtime using SATP characteristic, use the global variable pgtable_l4_enabled to output mmu type of the processor through /proc/cpuinfo instead of relying on device tree infos. Signed-off-by: Alexandre Ghiti Reviewed-by: Anup Patel Reviewed-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpu.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) (limited to 'arch/riscv/kernel') diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index f13b2c9ea912..ad0a7e9f828b 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -7,6 +7,7 @@ #include #include #include +#include /* * Returns the hart ID of the given device tree node, or -ENODEV if the node @@ -71,18 +72,19 @@ static void print_isa(struct seq_file *f, const char *isa) seq_puts(f, "\n"); } -static void print_mmu(struct seq_file *f, const char *mmu_type) +static void print_mmu(struct seq_file *f) { + char sv_type[16]; + #if defined(CONFIG_32BIT) - if (strcmp(mmu_type, "riscv,sv32") != 0) - return; + strncpy(sv_type, "sv32", 5); #elif defined(CONFIG_64BIT) - if (strcmp(mmu_type, "riscv,sv39") != 0 && - strcmp(mmu_type, "riscv,sv48") != 0) - return; + if (pgtable_l4_enabled) + strncpy(sv_type, "sv48", 5); + else + strncpy(sv_type, "sv39", 5); #endif - - seq_printf(f, "mmu\t\t: %s\n", mmu_type+6); + seq_printf(f, "mmu\t\t: %s\n", sv_type); } static void *c_start(struct seq_file *m, loff_t *pos) @@ -107,14 +109,13 @@ static int c_show(struct seq_file *m, void *v) { unsigned long cpu_id = (unsigned long)v - 1; struct device_node *node = of_get_cpu_node(cpu_id, NULL); - const char *compat, *isa, *mmu; + const char *compat, *isa; seq_printf(m, "processor\t: %lu\n", cpu_id); seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id)); if (!of_property_read_string(node, "riscv,isa", &isa)) print_isa(m, isa); - if (!of_property_read_string(node, "mmu-type", &mmu)) - print_mmu(m, mmu); + print_mmu(m); if (!of_property_read_string(node, "compatible", &compat) && strcmp(compat, "riscv")) seq_printf(m, "uarch\t\t: %s\n", compat); -- cgit v1.2.3