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Diffstat (limited to 'drivers/firmware/efi/libstub/arm32-stub.c')
-rw-r--r--drivers/firmware/efi/libstub/arm32-stub.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
new file mode 100644
index 000000000..0131e3aaa
--- /dev/null
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
+ */
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+static efi_guid_t cpu_state_guid = LINUX_EFI_ARM_CPU_STATE_TABLE_GUID;
+
+struct efi_arm_entry_state *efi_entry_state;
+
+static void get_cpu_state(u32 *cpsr, u32 *sctlr)
+{
+ asm("mrs %0, cpsr" : "=r"(*cpsr));
+ if ((*cpsr & MODE_MASK) == HYP_MODE)
+ asm("mrc p15, 4, %0, c1, c0, 0" : "=r"(*sctlr));
+ else
+ asm("mrc p15, 0, %0, c1, c0, 0" : "=r"(*sctlr));
+}
+
+efi_status_t check_platform_features(void)
+{
+ efi_status_t status;
+ u32 cpsr, sctlr;
+ int block;
+
+ get_cpu_state(&cpsr, &sctlr);
+
+ efi_info("Entering in %s mode with MMU %sabled\n",
+ ((cpsr & MODE_MASK) == HYP_MODE) ? "HYP" : "SVC",
+ (sctlr & 1) ? "en" : "dis");
+
+ status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
+ sizeof(*efi_entry_state),
+ (void **)&efi_entry_state);
+ if (status != EFI_SUCCESS) {
+ efi_err("allocate_pool() failed\n");
+ return status;
+ }
+
+ efi_entry_state->cpsr_before_ebs = cpsr;
+ efi_entry_state->sctlr_before_ebs = sctlr;
+
+ status = efi_bs_call(install_configuration_table, &cpu_state_guid,
+ efi_entry_state);
+ if (status != EFI_SUCCESS) {
+ efi_err("install_configuration_table() failed\n");
+ goto free_state;
+ }
+
+ /* non-LPAE kernels can run anywhere */
+ if (!IS_ENABLED(CONFIG_ARM_LPAE))
+ return EFI_SUCCESS;
+
+ /* LPAE kernels need compatible hardware */
+ block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
+ if (block < 5) {
+ efi_err("This LPAE kernel is not supported by your CPU\n");
+ status = EFI_UNSUPPORTED;
+ goto drop_table;
+ }
+ return EFI_SUCCESS;
+
+drop_table:
+ efi_bs_call(install_configuration_table, &cpu_state_guid, NULL);
+free_state:
+ efi_bs_call(free_pool, efi_entry_state);
+ return status;
+}
+
+void efi_handle_post_ebs_state(void)
+{
+ get_cpu_state(&efi_entry_state->cpsr_after_ebs,
+ &efi_entry_state->sctlr_after_ebs);
+}
+
+static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
+
+struct screen_info *alloc_screen_info(void)
+{
+ struct screen_info *si;
+ efi_status_t status;
+
+ /*
+ * Unlike on arm64, where we can directly fill out the screen_info
+ * structure from the stub, we need to allocate a buffer to hold
+ * its contents while we hand over to the kernel proper from the
+ * decompressor.
+ */
+ status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
+ sizeof(*si), (void **)&si);
+
+ if (status != EFI_SUCCESS)
+ return NULL;
+
+ status = efi_bs_call(install_configuration_table,
+ &screen_info_guid, si);
+ if (status == EFI_SUCCESS)
+ return si;
+
+ efi_bs_call(free_pool, si);
+ return NULL;
+}
+
+void free_screen_info(struct screen_info *si)
+{
+ if (!si)
+ return;
+
+ efi_bs_call(install_configuration_table, &screen_info_guid, NULL);
+ efi_bs_call(free_pool, si);
+}
+
+efi_status_t handle_kernel_image(unsigned long *image_addr,
+ unsigned long *image_size,
+ unsigned long *reserve_addr,
+ unsigned long *reserve_size,
+ efi_loaded_image_t *image,
+ efi_handle_t image_handle)
+{
+ const int slack = TEXT_OFFSET - 5 * PAGE_SIZE;
+ int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN;
+ unsigned long alloc_base, kernel_base;
+ efi_status_t status;
+
+ /*
+ * Allocate space for the decompressed kernel as low as possible.
+ * The region should be 16 MiB aligned, but the first 'slack' bytes
+ * are not used by Linux, so we allow those to be occupied by the
+ * firmware.
+ */
+ status = efi_low_alloc_above(alloc_size, EFI_PAGE_SIZE, &alloc_base, 0x0);
+ if (status != EFI_SUCCESS) {
+ efi_err("Unable to allocate memory for uncompressed kernel.\n");
+ return status;
+ }
+
+ if ((alloc_base % EFI_PHYS_ALIGN) > slack) {
+ /*
+ * More than 'slack' bytes are already occupied at the base of
+ * the allocation, so we need to advance to the next 16 MiB block.
+ */
+ kernel_base = round_up(alloc_base, EFI_PHYS_ALIGN);
+ efi_info("Free memory starts at 0x%lx, setting kernel_base to 0x%lx\n",
+ alloc_base, kernel_base);
+ } else {
+ kernel_base = round_down(alloc_base, EFI_PHYS_ALIGN);
+ }
+
+ *reserve_addr = kernel_base + slack;
+ *reserve_size = MAX_UNCOMP_KERNEL_SIZE;
+
+ /* now free the parts that we will not use */
+ if (*reserve_addr > alloc_base) {
+ efi_bs_call(free_pages, alloc_base,
+ (*reserve_addr - alloc_base) / EFI_PAGE_SIZE);
+ alloc_size -= *reserve_addr - alloc_base;
+ }
+ efi_bs_call(free_pages, *reserve_addr + MAX_UNCOMP_KERNEL_SIZE,
+ (alloc_size - MAX_UNCOMP_KERNEL_SIZE) / EFI_PAGE_SIZE);
+
+ *image_addr = kernel_base + TEXT_OFFSET;
+ *image_size = 0;
+
+ efi_debug("image addr == 0x%lx, reserve_addr == 0x%lx\n",
+ *image_addr, *reserve_addr);
+
+ return EFI_SUCCESS;
+}