The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=fbec1f91951fe01c1c590bab5e6c16a30884f352
commit fbec1f91951fe01c1c590bab5e6c16a30884f352 Author: Mark Johnston <[email protected]> AuthorDate: 2023-06-28 20:12:47 +0000 Commit: Mark Johnston <[email protected]> CommitDate: 2023-06-28 20:29:49 +0000 arm64: Add a masked get_kernel_reg() This lets consumers fetch the value of a system register and apply a mask over individual fields. That is, each field in the returned value will be the "smaller" of the two provided by "mask" and the value saved in kern_cpu_desc. This will be used by vmm to sanitize host system register fields. Reviewed by: andrew MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Sponsored by: Klara, Inc. (hardware) Differential Revision: https://reviews.freebsd.org/D40500 --- sys/arm64/arm64/identcpu.c | 90 +++++++++++++++++++++++++++++----------------- sys/arm64/include/cpu.h | 1 + 2 files changed, 59 insertions(+), 32 deletions(-) diff --git a/sys/arm64/arm64/identcpu.c b/sys/arm64/arm64/identcpu.c index e96f0a089784..01e663ff47c2 100644 --- a/sys/arm64/arm64/identcpu.c +++ b/sys/arm64/arm64/identcpu.c @@ -1721,38 +1721,6 @@ user_mrs_handler(vm_offset_t va, uint32_t insn, struct trapframe *frame, return (1); } -bool -extract_user_id_field(u_int reg, u_int field_shift, uint8_t *val) -{ - uint64_t value; - int i; - - for (i = 0; i < nitems(user_regs); i++) { - if (user_regs[i].reg == reg) { - value = CPU_DESC_FIELD(user_cpu_desc, i); - *val = value >> field_shift; - return (true); - } - } - - return (false); -} - -bool -get_kernel_reg(u_int reg, uint64_t *val) -{ - int i; - - for (i = 0; i < nitems(user_regs); i++) { - if (user_regs[i].reg == reg) { - *val = CPU_DESC_FIELD(kern_cpu_desc, i); - return (true); - } - } - - return (false); -} - /* * Compares two field values that may be signed or unsigned. * Returns: @@ -1808,6 +1776,64 @@ update_lower_register(uint64_t val, uint64_t new_val, u_int shift, return (val); } +bool +extract_user_id_field(u_int reg, u_int field_shift, uint8_t *val) +{ + uint64_t value; + int i; + + for (i = 0; i < nitems(user_regs); i++) { + if (user_regs[i].reg == reg) { + value = CPU_DESC_FIELD(user_cpu_desc, i); + *val = value >> field_shift; + return (true); + } + } + + return (false); +} + +bool +get_kernel_reg(u_int reg, uint64_t *val) +{ + int i; + + for (i = 0; i < nitems(user_regs); i++) { + if (user_regs[i].reg == reg) { + *val = CPU_DESC_FIELD(kern_cpu_desc, i); + return (true); + } + } + + return (false); +} + +/* + * Fetch the specified register's value, ensuring that individual field values + * do not exceed those in the mask. + */ +bool +get_kernel_reg_masked(u_int reg, uint64_t *valp, uint64_t mask) +{ + struct mrs_field *fields; + uint64_t val; + + for (int i = 0; i < nitems(user_regs); i++) { + if (user_regs[i].reg == reg) { + val = CPU_DESC_FIELD(kern_cpu_desc, i); + *valp = 0; + fields = user_regs[i].fields; + for (int j = 0; fields[j].type != 0; j++) { + *valp |= update_lower_register(mask, val, + fields[j].shift, 4, fields[j].sign); + } + return (true); + } + } + + return (false); +} + void update_special_regs(u_int cpu) { diff --git a/sys/arm64/include/cpu.h b/sys/arm64/include/cpu.h index 1ea497756698..0bb320f2e0a0 100644 --- a/sys/arm64/include/cpu.h +++ b/sys/arm64/include/cpu.h @@ -213,6 +213,7 @@ void ptrauth_mp_start(uint64_t); void update_special_regs(u_int); bool extract_user_id_field(u_int, u_int, uint8_t *); bool get_kernel_reg(u_int, uint64_t *); +bool get_kernel_reg_masked(u_int, uint64_t *, uint64_t); void cpu_desc_init(void);
