diff options
| -rw-r--r-- | Documentation/arch/arm64/sve.rst | 5 | ||||
| -rw-r--r-- | arch/arm64/kernel/ptrace.c | 40 |
2 files changed, 38 insertions, 7 deletions
diff --git a/Documentation/arch/arm64/sve.rst b/Documentation/arch/arm64/sve.rst index 28152492c29c..a61c9d0efe4d 100644 --- a/Documentation/arch/arm64/sve.rst +++ b/Documentation/arch/arm64/sve.rst @@ -402,6 +402,11 @@ The regset data starts with struct user_sve_header, containing: streaming mode and any SETREGSET of NT_ARM_SSVE will enter streaming mode if the target was not in streaming mode. +* On systems that do not support SVE it is permitted to use SETREGSET to + write SVE_PT_REGS_FPSIMD formatted data via NT_ARM_SVE, in this case the + vector length should be specified as 0. This allows streaming mode to be + disabled on systems with SME but not SVE. + * If any register data is provided along with SVE_PT_VL_ONEXEC then the registers data will be interpreted with the current vector length, not the vector length configured for use on exec. diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 4b001121c72d..b9bdd83fbbca 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -912,13 +912,39 @@ static int sve_set_common(struct task_struct *target, return -EINVAL; /* - * Apart from SVE_PT_REGS_MASK, all SVE_PT_* flags are consumed by - * vec_set_vector_length(), which will also validate them for us: + * On systems without SVE we accept FPSIMD format writes with + * a VL of 0 to allow exiting streaming mode, otherwise a VL + * is required. */ - ret = vec_set_vector_length(target, type, header.vl, - ((unsigned long)header.flags & ~SVE_PT_REGS_MASK) << 16); - if (ret) - return ret; + if (header.vl) { + /* + * If the system does not support SVE we can't + * configure a SVE VL. + */ + if (!system_supports_sve() && type == ARM64_VEC_SVE) + return -EINVAL; + + /* + * Apart from SVE_PT_REGS_MASK, all SVE_PT_* flags are + * consumed by vec_set_vector_length(), which will + * also validate them for us: + */ + ret = vec_set_vector_length(target, type, header.vl, + ((unsigned long)header.flags & ~SVE_PT_REGS_MASK) << 16); + if (ret) + return ret; + } else { + /* If the system supports SVE we require a VL. */ + if (system_supports_sve()) + return -EINVAL; + + /* + * Only FPSIMD formatted data with no flags set is + * supported. + */ + if (header.flags != SVE_PT_REGS_FPSIMD) + return -EINVAL; + } /* Allocate SME storage if necessary, preserving any existing ZA/ZT state */ if (type == ARM64_VEC_SME) { @@ -1016,7 +1042,7 @@ static int sve_set(struct task_struct *target, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { - if (!system_supports_sve()) + if (!system_supports_sve() && !system_supports_sme()) return -EINVAL; return sve_set_common(target, regset, pos, count, kbuf, ubuf, |