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| author | Samuel Holland <samuel.holland@sifive.com> | 2023-08-02 18:26:06 -0700 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-08-08 15:28:25 -0700 |
| commit | 6514f81e1bd55cbe419a5001a4ce910acc276211 (patch) | |
| tree | a72459616586bc3e86252c26d6a37e11f26e68c7 /arch/riscv/kernel/cpu.c | |
| parent | c3bcc65d4d2e8292c435322cbc34c318d06b8b6c (diff) | |
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 <palmer@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230803012608.3540081-1-samuel.holland@sifive.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/kernel/cpu.c')
| -rw-r--r-- | arch/riscv/kernel/cpu.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index a2fc952318e9..35b854cf078e 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -17,6 +17,11 @@ #include <asm/smp.h> #include <asm/pgtable.h> +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. |