Unverified Commit 3c2e0aff authored by Samuel Holland's avatar Samuel Holland Committed by Palmer Dabbelt
Browse files

riscv: hwprobe: Export the Supm ISA extension 



Supm is a virtual ISA extension defined in the RISC-V Pointer Masking
specification, which indicates that pointer masking is available in
U-mode. It can be provided by either Smnpm or Ssnpm, depending on which
mode the kernel runs in. Userspace should not care about this
distinction, so export Supm instead of either underlying extension.

Hide the extension if the kernel was compiled without support for the
pointer masking prctl() interface.

Signed-off-by: default avatarSamuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20241016202814.4061541-9-samuel.holland@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 7470b5af

Documentation/arch/riscv/hwprobe.rst

+3 −0
Original line number Diff line number Diff line
@@ -239,6 +239,9 @@ The following keys are defined: 
       ratified in commit 98918c844281 ("Merge pull request #1217 from

       riscv/zawrs") of riscv-isa-manual.



  * :c:macro:`RISCV_HWPROBE_EXT_SUPM`: The Supm extension is supported as

       defined in version 1.0 of the RISC-V Pointer Masking extensions.



* :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to

     :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was

     mistakenly classified as a bitmask rather than a value.

arch/riscv/include/uapi/asm/hwprobe.h

+1 −0
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ struct riscv_hwprobe { 
#define		RISCV_HWPROBE_EXT_ZCF		(1ULL << 46)

#define		RISCV_HWPROBE_EXT_ZCMOP		(1ULL << 47)

#define		RISCV_HWPROBE_EXT_ZAWRS		(1ULL << 48)

#define		RISCV_HWPROBE_EXT_SUPM		(1ULL << 49)

#define RISCV_HWPROBE_KEY_CPUPERF_0	5

#define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)

#define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)

arch/riscv/kernel/sys_hwprobe.c

+3 −0
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair, 
			EXT_KEY(ZFH);

			EXT_KEY(ZFHMIN);

		}



		if (IS_ENABLED(CONFIG_RISCV_ISA_SUPM))

			EXT_KEY(SUPM);

#undef EXT_KEY

	}