[RFT PATCH v3 2/9] RISC-V: Add early ioremap support

Atish Patra atish.patra at wdc.com
Thu Jul 16 19:40:57 EDT 2020


UEFI uses early IO or memory mappings for runtime services before
normal ioremap() is usable. Add the necessary fixmap bindings and
pmd mappings for generic ioremap support to work.

Signed-off-by: Atish Patra <atish.patra at wdc.com>
---
 arch/riscv/Kconfig              |  1 +
 arch/riscv/include/asm/Kbuild   |  1 +
 arch/riscv/include/asm/fixmap.h | 13 +++++++++++++
 arch/riscv/include/asm/io.h     |  1 +
 arch/riscv/kernel/setup.c       |  1 +
 arch/riscv/mm/init.c            | 33 +++++++++++++++++++++++++++++++++
 6 files changed, 50 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 3230c1d48562..e6c1c98a53fb 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -34,6 +34,7 @@ config RISCV
 	select GENERIC_ARCH_TOPOLOGY if SMP
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_EARLY_IOREMAP
 	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
 	select GENERIC_IOREMAP
 	select GENERIC_IRQ_MULTI_HANDLER
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 3d9410bb4de0..59dd7be55005 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+generic-y += early_ioremap.h
 generic-y += extable.h
 generic-y += flat.h
 generic-y += kvm_para.h
diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
index 11613f38228a..54cbf07fb4e9 100644
--- a/arch/riscv/include/asm/fixmap.h
+++ b/arch/riscv/include/asm/fixmap.h
@@ -27,6 +27,19 @@ enum fixed_addresses {
 	FIX_TEXT_POKE1,
 	FIX_TEXT_POKE0,
 	FIX_EARLYCON_MEM_BASE,
+
+	__end_of_permanent_fixed_addresses,
+	/*
+	 * Temporary boot-time mappings, used by early_ioremap(),
+	 * before ioremap() is functional.
+	 */
+#define NR_FIX_BTMAPS		(SZ_256K / PAGE_SIZE)
+#define FIX_BTMAPS_SLOTS	7
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+
+	FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+	FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
+
 	__end_of_fixed_addresses
 };
 
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index 3835c3295dc5..c025a746a148 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -14,6 +14,7 @@
 #include <linux/types.h>
 #include <linux/pgtable.h>
 #include <asm/mmiowb.h>
+#include <asm/early_ioremap.h>
 
 /*
  * MMIO access functions are separated out to break dependency cycles
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 8519a6d29857..1244b433fe7c 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -72,6 +72,7 @@ void __init setup_arch(char **cmdline_p)
 
 	*cmdline_p = boot_command_line;
 
+	early_ioremap_setup();
 	parse_early_param();
 
 	setup_bootmem();
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 5e9328fa635b..62c90161765f 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -401,6 +401,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	uintptr_t load_pa = (uintptr_t)(&_start);
 	uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
 	uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
+#ifndef __PAGETABLE_PMD_FOLDED
+	pmd_t fix_bmap_spmd, fix_bmap_epmd;
+#endif
 
 	va_pa_offset = PAGE_OFFSET - load_pa;
 	pfn_base = PFN_DOWN(load_pa);
@@ -451,6 +454,36 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	dtb_size = fdt_totalsize((void *)dtb_pa);
 	dtb_size = (dtb_size > DTB_EARLY_SIZE) ? DTB_EARLY_SIZE : dtb_size;
 	memcpy((void *)pa, (void *)dtb_pa, dtb_size);
+
+	/*
+	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
+	 * range can not span multiple pmds.
+	 */
+	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+#ifndef __PAGETABLE_PMD_FOLDED
+	/*
+	 * Early ioremap fixmap is already created as it lies within first 2MB
+	 * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
+	 * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
+	 * the user if not.
+	 */
+	fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
+	fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
+	if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
+		WARN_ON(1);
+		pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
+			pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
+		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+			fix_to_virt(FIX_BTMAP_BEGIN));
+		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+			fix_to_virt(FIX_BTMAP_END));
+
+		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
+	}
+#endif
 }
 
 static void __init setup_vm_final(void)
-- 
2.24.0




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