From 6514f81e1bd55cbe419a5001a4ce910acc276211 Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Wed, 2 Aug 2023 18:26:06 -0700 Subject: [PATCH] riscv: Fix CPU feature detection with SMP disabled commit 914d6f44fc50 ("RISC-V: only iterate over possible CPUs in ISA string parser") changed riscv_fill_hwcap() from iterating over CPU DT nodes to iterating over logical CPU IDs. Since this function runs long before cpu_dev_init() creates CPU devices, it hits the fallback path in of_cpu_device_node_get(), which itself iterates over the DT nodes, searching for a node with the requested CPU ID. (Incidentally, this makes riscv_fill_hwcap() now take quadratic time.) riscv_fill_hwcap() passes a logical CPU ID to of_cpu_device_node_get(), which uses the arch_match_cpu_phys_id() hook to translate the logical ID to a physical ID as found in the DT. arch_match_cpu_phys_id() has a generic weak definition, and RISC-V provides a strong definition using cpuid_to_hartid_map(). However, the RISC-V specific implementation is located in arch/riscv/kernel/smp.c, and that file is only compiled when SMP is enabled. As a result, when SMP is disabled, the generic definition is used, and riscv_isa gets initialized based on the ISA string of hart 0, not the boot hart. On FU740, this means has_fpu() returns false, and userspace crashes when trying to use floating-point instructions. Fix this by moving arch_match_cpu_phys_id() to a file which is always compiled. Fixes: 70114560b285 ("RISC-V: Add RISC-V specific arch_match_cpu_phys_id") Fixes: 914d6f44fc50 ("RISC-V: only iterate over possible CPUs in ISA string parser") Reported-by: Palmer Dabbelt Signed-off-by: Samuel Holland Reviewed-by: Conor Dooley Link: https://lore.kernel.org/r/20230803012608.3540081-1-samuel.holland@sifive.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpu.c | 5 +++++ arch/riscv/kernel/smp.c | 5 ----- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index a2fc952..35b854c 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -17,6 +17,11 @@ #include #include +bool arch_match_cpu_phys_id(int cpu, u64 phys_id) +{ + return phys_id == cpuid_to_hartid_map(cpu); +} + /* * Returns the hart ID of the given device tree node, or -ENODEV if the node * isn't an enabled and valid RISC-V hart node. diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 85bbce0..40420af 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -61,11 +61,6 @@ int riscv_hartid_to_cpuid(unsigned long hartid) return -ENOENT; } -bool arch_match_cpu_phys_id(int cpu, u64 phys_id) -{ - return phys_id == cpuid_to_hartid_map(cpu); -} - static void ipi_stop(void) { set_cpu_online(smp_processor_id(), false); -- 2.7.4