From fa5eded303ac25c95ca4300ebfb4788c149bf2ab Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Thu, 28 May 2020 21:21:49 -0600 Subject: cpu/x86/mtrr: add helper for setting multiple MTRRs Introduce concept of var_mtrr_context object for tracking and assigning MTRR values. The algorithm is lifted from postcar_loader code, but it's generalized for different type of users: setting MSRs explicitly or deferring to a particular caller's desired actions. BUG=b:155426691,b:155322763 Change-Id: Ic03b4b617196f04071093bbba4cf28d23fa482d8 Signed-off-by: Aaron Durbin Reviewed-on: https://review.coreboot.org/c/coreboot/+/41849 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh --- src/include/cpu/x86/mtrr.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'src/include') diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h index 301ea3052d..c1ee51accf 100644 --- a/src/include/cpu/x86/mtrr.h +++ b/src/include/cpu/x86/mtrr.h @@ -110,6 +110,37 @@ void clear_all_var_mtrr(void); asmlinkage void display_mtrrs(void); +/* Variable MTRR structure to help track and set MTRRs prior to ramstage. This + and the following APIs can be used to set up more complex MTRR solutions + instead of open coding get_free_var_mtrr() and set_var_mtrr() or for determining + a future solution, such as postcar_loader. */ +struct var_mtrr_context { + uint32_t upper_mask; + int max_var_mtrrs; + int used_var_mtrrs; + void *arg; /* optional callback parameter */ +}; + +/* Returns 0-relative MTRR from context. Use MTRR_PHYS_BASE|MASK macros for calculating + MSR address value. */ +static inline int var_mtrr_context_current_mtrr(const struct var_mtrr_context *ctx) +{ + return ctx->used_var_mtrrs; +} + +/* Initialize var_mtrr_context object. Assumes all variable MTRRs are not yet used. */ +void var_mtrr_context_init(struct var_mtrr_context *ctx, void *arg); +/* Allocate a variable mtrr base and mask, calling the provided callback for each MTRR + MSR base-mask pair needed to accommodate the address and size request. + Returns < 0 on error and 0 on success. */ +int var_mtrr_set_with_cb(struct var_mtrr_context *ctx, + uintptr_t addr, size_t size, int type, + void (*callback)(const struct var_mtrr_context *ctx, + uintptr_t base_addr, size_t size, + msr_t base, msr_t mask)); +/* Same as var_mtrr_set_with_cb() but just write the MSRs directly. */ +int var_mtrr_set(struct var_mtrr_context *ctx, uintptr_t addr, size_t size, int type); + /* * Set the MTRRs using the data on the stack from setup_stack_and_mtrrs. * Return a new top_of_stack value which removes the setup_stack_and_mtrrs data. -- cgit v1.2.3