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/cpu/x86/mtrr/earlymtrr.c | 67 ++++++++++++++++++++++++++++++++++++++++++++ src/include/cpu/x86/mtrr.h | 31 ++++++++++++++++++++ 2 files changed, 98 insertions(+) diff --git a/src/cpu/x86/mtrr/earlymtrr.c b/src/cpu/x86/mtrr/earlymtrr.c index 5a2ce554fa..879b8eff27 100644 --- a/src/cpu/x86/mtrr/earlymtrr.c +++ b/src/cpu/x86/mtrr/earlymtrr.c @@ -65,3 +65,70 @@ void clear_all_var_mtrr(void) wrmsr(MTRR_PHYS_BASE(i), mtrr); } } + +void var_mtrr_context_init(struct var_mtrr_context *ctx, void *arg) +{ + ctx->upper_mask = (1U << (cpu_phys_address_size() - 32)) - 1; + ctx->max_var_mtrrs = get_var_mtrr_count(); + ctx->used_var_mtrrs = 0; + ctx->arg = arg; +} + +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)) +{ + /* Utilize additional MTRRs if the specified size is greater than the + base address alignment. */ + while (size != 0) { + uint32_t addr_lsb; + uint32_t size_msb; + uint32_t mtrr_size; + msr_t base; + msr_t mask; + + if (ctx->used_var_mtrrs >= ctx->max_var_mtrrs) { + printk(BIOS_ERR, "No more variable MTRRs: %d\n", + ctx->max_var_mtrrs); + return -1; + } + + addr_lsb = fls(addr); + size_msb = fms(size); + + /* All MTRR entries need to have their base aligned to the mask + size. The maximum size is calculated by a function of the + min base bit set and maximum size bit set. */ + if (addr_lsb > size_msb) + mtrr_size = 1 << size_msb; + else + mtrr_size = 1 << addr_lsb; + + base.hi = (uint64_t)addr >> 32; + base.lo = addr | type; + mask.hi = ctx->upper_mask; + mask.lo = ~(mtrr_size - 1) | MTRR_PHYS_MASK_VALID; + callback(ctx, addr, mtrr_size, base, mask); + ctx->used_var_mtrrs++; + + size -= mtrr_size; + addr += mtrr_size; + } + + return 0; +} + +static void set_mtrr(const struct var_mtrr_context *ctx, uintptr_t base_addr, size_t size, + msr_t base, msr_t mask) +{ + int i = var_mtrr_context_current_mtrr(ctx); + + wrmsr(MTRR_PHYS_BASE(i), base); + wrmsr(MTRR_PHYS_MASK(i), mask); +} + +int var_mtrr_set(struct var_mtrr_context *ctx, uintptr_t addr, size_t size, int type) +{ + return var_mtrr_set_with_cb(ctx, addr, size, type, set_mtrr); +} 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