[PATCH v5 0/6] Fixmap support and MM cleanups

[PATCH v5 0/6] Fixmap support and MM cleanups

[Anup Patel]

This patchset does:
1. Moves MM related code from kernel/setup.c to mm/init.c
2. Implements compile-time fixed mappings

Using fixed mappings, we get earlyprints even without SBI calls.

For example, we can now use kernel parameter
"earlycon=uart8250,mmio,0x10000000"
to get early prints on QEMU virt machine without using SBI calls.

The patchset is tested on QEMU virt machine. It is based on
Linux-5.0-rc6 and can be found at riscv_fixmap_v5 branch of:
https://github.com/avpatel/linux.git.

Changes since v4:
 - Use free_reserved_area() instead of memblock_free() in PATCH6

Changes since v3:
 - Re-worked and simplified PATCH6

Changes since v2:
 - Fixed commit description of PATCH6
 - Ensured commit description of all PATCH use upto 72
   characters per line

Changes since v1:
 - Use more characters per line in changelog of PATCH3
 - Removed #ifndef __ASSEMBLY__ from PATCH5
 - Use more characters per line in commets of PATCH5
 - Added PATCH6 to implement keepinitrd kernel parameter

Anup Patel (6):
  RISC-V: Move free_initrd_mem() to kernel/setup.c
  RISC-V: Setup init_mm before parse_early_param()
  RISC-V: Move setup_bootmem() to mm/init.c
  RISC-V: Move setup_vm() to mm/init.c
  RISC-V: Implement compile-time fixed mappings
  RISC-V: Free-up initrd in free_initrd_mem()

 arch/riscv/Kconfig               |   3 +
 arch/riscv/include/asm/fixmap.h  |  44 +++++++++++
 arch/riscv/include/asm/pgtable.h |   1 +
 arch/riscv/kernel/setup.c        | 107 +++-----------------------
 arch/riscv/mm/init.c             | 124 ++++++++++++++++++++++++++++++-
 5 files changed, 180 insertions(+), 99 deletions(-)
 create mode 100644 arch/riscv/include/asm/fixmap.h

-- 
2.17.1

[PATCH v5 1/6] RISC-V: Move free_initrd_mem() to kernel/setup.c

[Anup Patel]

We move free_initrd_mem() to kernel/setup.c so that all initrd related
functions are in one place.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/kernel/setup.c | 4 ++++
 arch/riscv/mm/init.c      | 7 -------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 77564310235f..36f60b4d2147 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -96,6 +96,10 @@ static void __init setup_initrd(void)
 	initrd_start = 0;
 	initrd_end = 0;
 }
+
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+}
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 658ebf645f42..504a5e491f5a 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -14,7 +14,6 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/memblock.h>
-#include <linux/initrd.h>
 #include <linux/swap.h>
 #include <linux/sizes.h>
 
@@ -64,9 +63,3 @@ void free_initmem(void)
 {
 	free_initmem_default(0);
 }
-
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-}
-#endif /* CONFIG_BLK_DEV_INITRD */
-- 
2.17.1

Re: [PATCH v5 1/6] RISC-V: Move free_initrd_mem() to kernel/setup.c

[Mike Rapoport]

On Wed, Feb 13, 2019 at 08:07:17AM +0000, Anup Patel wrote:
> We move free_initrd_mem() to kernel/setup.c so that all initrd related
> functions are in one place.

A few patches after you move setup_bootmem() that calls setup_initrd() to
mm/init.c. I'd say it makes more sense to move setup_intird() to
mm/init.c.
 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
> ---
>  arch/riscv/kernel/setup.c | 4 ++++
>  arch/riscv/mm/init.c      | 7 -------
>  2 files changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 77564310235f..36f60b4d2147 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -96,6 +96,10 @@ static void __init setup_initrd(void)
>  	initrd_start = 0;
>  	initrd_end = 0;
>  }
> +
> +void free_initrd_mem(unsigned long start, unsigned long end)
> +{
> +}
>  #endif /* CONFIG_BLK_DEV_INITRD */
>  
>  pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 658ebf645f42..504a5e491f5a 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -14,7 +14,6 @@
>  #include <linux/init.h>
>  #include <linux/mm.h>
>  #include <linux/memblock.h>
> -#include <linux/initrd.h>
>  #include <linux/swap.h>
>  #include <linux/sizes.h>
>  
> @@ -64,9 +63,3 @@ void free_initmem(void)
>  {
>  	free_initmem_default(0);
>  }
> -
> -#ifdef CONFIG_BLK_DEV_INITRD
> -void free_initrd_mem(unsigned long start, unsigned long end)
> -{
> -}
> -#endif /* CONFIG_BLK_DEV_INITRD */
> -- 
> 2.17.1
> 

-- 
Sincerely yours,
Mike.

RE: [PATCH v5 1/6] RISC-V: Move free_initrd_mem() to kernel/setup.c

[Anup Patel]

> -----Original Message-----
> From: Mike Rapoport [mailto:rppt@linux.ibm.com]
> Sent: Wednesday, February 13, 2019 3:30 PM
> To: Anup Patel <Anup.Patel@wdc.com>
> Cc: Palmer Dabbelt <palmer@sifive.com>; Albert Ou
> <aou@eecs.berkeley.edu>; Atish Patra <Atish.Patra@wdc.com>; Paul
> Walmsley <paul.walmsley@sifive.com>; Christoph Hellwig
> <hch@infradead.org>; linux-riscv@lists.infradead.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v5 1/6] RISC-V: Move free_initrd_mem() to
> kernel/setup.c
> 
> On Wed, Feb 13, 2019 at 08:07:17AM +0000, Anup Patel wrote:
> > We move free_initrd_mem() to kernel/setup.c so that all initrd related
> > functions are in one place.
> 
> A few patches after you move setup_bootmem() that calls setup_initrd() to
> mm/init.c. I'd say it makes more sense to move setup_intird() to mm/init.c.

Makes sense. I will drop this patch and I will move setup_initrd() to
mm/init.c along with setup_bootmem() because setup_bootmem()
depends on setup_initrd().

Regards,
Anup

[PATCH v5 2/6] RISC-V: Setup init_mm before parse_early_param()

[Anup Patel]

We should setup init_mm before doing parse_early_param() in setup_arch()
to be consistent with setup_arch() of other architectures such as x86,
ARM, and ARM64.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/kernel/setup.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 36f60b4d2147..9e6395b7d409 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -208,15 +208,15 @@ static void __init setup_bootmem(void)
 
 void __init setup_arch(char **cmdline_p)
 {
-	*cmdline_p = boot_command_line;
-
-	parse_early_param();
-
 	init_mm.start_code = (unsigned long) _stext;
 	init_mm.end_code   = (unsigned long) _etext;
 	init_mm.end_data   = (unsigned long) _edata;
 	init_mm.brk        = (unsigned long) _end;
 
+	*cmdline_p = boot_command_line;
+
+	parse_early_param();
+
 	setup_bootmem();
 	paging_init();
 	unflatten_device_tree();
@@ -235,4 +235,3 @@ void __init setup_arch(char **cmdline_p)
 
 	riscv_fill_hwcap();
 }
-
-- 
2.17.1

[PATCH v5 3/6] RISC-V: Move setup_bootmem() to mm/init.c

[Anup Patel]

The setup_bootmem() mainly populates memblocks and does early memory
reservations. The right location for this function is mm/init.c.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/include/asm/pgtable.h |  1 +
 arch/riscv/kernel/setup.c        | 48 ++++----------------------------
 arch/riscv/mm/init.c             | 40 ++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 43 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 16301966d65b..35893810cba3 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -404,6 +404,7 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
 #define kern_addr_valid(addr)   (1) /* FIXME */
 #endif
 
+extern void setup_bootmem(void);
 extern void paging_init(void);
 
 static inline void pgtable_cache_init(void)
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 9e6395b7d409..ab29a66a17fc 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -163,49 +163,6 @@ void __init parse_dtb(unsigned int hartid, void *dtb)
 #endif
 }
 
-static void __init setup_bootmem(void)
-{
-	struct memblock_region *reg;
-	phys_addr_t mem_size = 0;
-
-	/* Find the memory region containing the kernel */
-	for_each_memblock(memory, reg) {
-		phys_addr_t vmlinux_end = __pa(_end);
-		phys_addr_t end = reg->base + reg->size;
-
-		if (reg->base <= vmlinux_end && vmlinux_end <= end) {
-			/*
-			 * Reserve from the start of the region to the end of
-			 * the kernel
-			 */
-			memblock_reserve(reg->base, vmlinux_end - reg->base);
-			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
-		}
-	}
-	BUG_ON(mem_size == 0);
-
-	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
-
-#ifdef CONFIG_BLK_DEV_INITRD
-	setup_initrd();
-#endif /* CONFIG_BLK_DEV_INITRD */
-
-	early_init_fdt_reserve_self();
-	early_init_fdt_scan_reserved_mem();
-	memblock_allow_resize();
-	memblock_dump_all();
-
-	for_each_memblock(memory, reg) {
-		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
-		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
-
-		memblock_set_node(PFN_PHYS(start_pfn),
-		                  PFN_PHYS(end_pfn - start_pfn),
-		                  &memblock.memory, 0);
-	}
-}
-
 void __init setup_arch(char **cmdline_p)
 {
 	init_mm.start_code = (unsigned long) _stext;
@@ -218,6 +175,11 @@ void __init setup_arch(char **cmdline_p)
 	parse_early_param();
 
 	setup_bootmem();
+
+#ifdef CONFIG_BLK_DEV_INITRD
+	setup_initrd();
+#endif /* CONFIG_BLK_DEV_INITRD */
+
 	paging_init();
 	unflatten_device_tree();
 
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 504a5e491f5a..a57dba8ac9e7 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -16,6 +16,7 @@
 #include <linux/memblock.h>
 #include <linux/swap.h>
 #include <linux/sizes.h>
+#include <linux/of_fdt.h>
 
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
@@ -63,3 +64,42 @@ void free_initmem(void)
 {
 	free_initmem_default(0);
 }
+
+void __init setup_bootmem(void)
+{
+	struct memblock_region *reg;
+	phys_addr_t mem_size = 0;
+
+	/* Find the memory region containing the kernel */
+	for_each_memblock(memory, reg) {
+		phys_addr_t vmlinux_end = __pa(_end);
+		phys_addr_t end = reg->base + reg->size;
+
+		if (reg->base <= vmlinux_end && vmlinux_end <= end) {
+			/*
+			 * Reserve from the start of the region to the end of
+			 * the kernel
+			 */
+			memblock_reserve(reg->base, vmlinux_end - reg->base);
+			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
+		}
+	}
+	BUG_ON(mem_size == 0);
+
+	set_max_mapnr(PFN_DOWN(mem_size));
+	max_low_pfn = memblock_end_of_DRAM();
+
+	early_init_fdt_reserve_self();
+	early_init_fdt_scan_reserved_mem();
+	memblock_allow_resize();
+	memblock_dump_all();
+
+	for_each_memblock(memory, reg) {
+		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
+		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
+
+		memblock_set_node(PFN_PHYS(start_pfn),
+				  PFN_PHYS(end_pfn - start_pfn),
+				  &memblock.memory, 0);
+	}
+}
-- 
2.17.1

[PATCH v5 4/6] RISC-V: Move setup_vm() to mm/init.c

[Anup Patel]

The setup_vm() is responsible for setting up initial page table hence
should be placed in mm/init.c.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/kernel/setup.c | 49 ---------------------------------------
 arch/riscv/mm/init.c      | 49 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 49 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index ab29a66a17fc..9cd583b6d1cd 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -102,55 +102,6 @@ void free_initrd_mem(unsigned long start, unsigned long end)
 }
 #endif /* CONFIG_BLK_DEV_INITRD */
 
-pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
-pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
-
-#ifndef __PAGETABLE_PMD_FOLDED
-#define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
-pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
-pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
-#endif
-
-asmlinkage void __init setup_vm(void)
-{
-	extern char _start;
-	uintptr_t i;
-	uintptr_t pa = (uintptr_t) &_start;
-	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);
-
-	va_pa_offset = PAGE_OFFSET - pa;
-	pfn_base = PFN_DOWN(pa);
-
-	/* Sanity check alignment and size */
-	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
-	BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);
-
-#ifndef __PAGETABLE_PMD_FOLDED
-	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
-		pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),
-			__pgprot(_PAGE_TABLE));
-	trampoline_pmd[0] = pfn_pmd(PFN_DOWN(pa), prot);
-
-	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
-		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
-		swapper_pg_dir[o] =
-			pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
-				__pgprot(_PAGE_TABLE));
-	}
-	for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
-		swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
-#else
-	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
-		pfn_pgd(PFN_DOWN(pa), prot);
-
-	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
-		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
-		swapper_pg_dir[o] =
-			pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
-	}
-#endif
-}
-
 void __init parse_dtb(unsigned int hartid, void *dtb)
 {
 	if (!early_init_dt_scan(__va(dtb)))
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index a57dba8ac9e7..7ed6ae90cf6b 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -103,3 +103,52 @@ void __init setup_bootmem(void)
 				  &memblock.memory, 0);
 	}
 }
+
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
+pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+
+#ifndef __PAGETABLE_PMD_FOLDED
+#define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
+pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
+pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+#endif
+
+asmlinkage void __init setup_vm(void)
+{
+	extern char _start;
+	uintptr_t i;
+	uintptr_t pa = (uintptr_t) &_start;
+	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);
+
+	va_pa_offset = PAGE_OFFSET - pa;
+	pfn_base = PFN_DOWN(pa);
+
+	/* Sanity check alignment and size */
+	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
+	BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);
+
+#ifndef __PAGETABLE_PMD_FOLDED
+	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),
+			__pgprot(_PAGE_TABLE));
+	trampoline_pmd[0] = pfn_pmd(PFN_DOWN(pa), prot);
+
+	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
+		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+		swapper_pg_dir[o] =
+			pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
+				__pgprot(_PAGE_TABLE));
+	}
+	for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
+		swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
+#else
+	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN(pa), prot);
+
+	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
+		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+		swapper_pg_dir[o] =
+			pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
+	}
+#endif
+}
-- 
2.17.1

[PATCH v5 5/6] RISC-V: Implement compile-time fixed mappings

[Anup Patel]

This patch implements compile-time virtual to physical mappings. These
compile-time fixed mappings can be used by earlycon, ACPI, and early
ioremap for creating fixed mappings when FIX_EARLYCON_MEM=y.

To start with, we have enabled compile-time fixed mappings for earlycon.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
---
 arch/riscv/Kconfig              |  3 +++
 arch/riscv/include/asm/fixmap.h | 44 +++++++++++++++++++++++++++++++++
 arch/riscv/mm/init.c            | 34 +++++++++++++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 arch/riscv/include/asm/fixmap.h

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 515fc3cc9687..3cfd10d35a28 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -89,6 +89,9 @@ config GENERIC_CSUM
 config GENERIC_HWEIGHT
 	def_bool y
 
+config FIX_EARLYCON_MEM
+	def_bool y
+
 config PGTABLE_LEVELS
 	int
 	default 3 if 64BIT
diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
new file mode 100644
index 000000000000..57afe604b495
--- /dev/null
+++ b/arch/riscv/include/asm/fixmap.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_FIXMAP_H
+#define _ASM_RISCV_FIXMAP_H
+
+#include <linux/kernel.h>
+#include <linux/sizes.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+/*
+ * Here we define all the compile-time 'special' virtual addresses.
+ * The point is to have a constant address at compile time, but to
+ * set the physical address only in the boot process.
+ *
+ * These 'compile-time allocated' memory buffers are page-sized. Use
+ * set_fixmap(idx,phys) to associate physical memory with fixmap indices.
+ */
+enum fixed_addresses {
+	FIX_HOLE,
+	FIX_EARLYCON_MEM_BASE,
+	__end_of_fixed_addresses
+};
+
+#define FIXADDR_SIZE		(__end_of_fixed_addresses * PAGE_SIZE)
+#define FIXADDR_TOP		(PAGE_OFFSET)
+#define FIXADDR_START		(FIXADDR_TOP - FIXADDR_SIZE)
+
+#define FIXMAP_PAGE_IO		PAGE_KERNEL
+
+#define __early_set_fixmap	__set_fixmap
+
+#define __late_set_fixmap	__set_fixmap
+#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
+
+extern void __set_fixmap(enum fixed_addresses idx,
+			 phys_addr_t phys, pgprot_t prot);
+
+#include <asm-generic/fixmap.h>
+
+#endif /* _ASM_RISCV_FIXMAP_H */
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 7ed6ae90cf6b..efcbdb9b3da3 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -18,6 +18,7 @@
 #include <linux/sizes.h>
 #include <linux/of_fdt.h>
 
+#include <asm/fixmap.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
 #include <asm/pgtable.h>
@@ -111,8 +112,28 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 #define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
 pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
 pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 #endif
 
+pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
+
+void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
+{
+	unsigned long addr = __fix_to_virt(idx);
+	pte_t *ptep;
+
+	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
+
+	ptep = &fixmap_pte[pte_index(addr)];
+
+	if (pgprot_val(prot)) {
+		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
+	} else {
+		pte_clear(&init_mm, addr, ptep);
+		local_flush_tlb_page(addr);
+	}
+}
+
 asmlinkage void __init setup_vm(void)
 {
 	extern char _start;
@@ -135,20 +156,33 @@ asmlinkage void __init setup_vm(void)
 
 	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+
 		swapper_pg_dir[o] =
 			pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
 				__pgprot(_PAGE_TABLE));
 	}
 	for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
 		swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
+
+	swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd),
+				__pgprot(_PAGE_TABLE));
+	fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] =
+		pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte),
+				__pgprot(_PAGE_TABLE));
 #else
 	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
 		pfn_pgd(PFN_DOWN(pa), prot);
 
 	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
 		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+
 		swapper_pg_dir[o] =
 			pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
 	}
+
+	swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte),
+				__pgprot(_PAGE_TABLE));
 #endif
 }
-- 
2.17.1

[PATCH v5 6/6] RISC-V: Free-up initrd in free_initrd_mem()

[Anup Patel]

We should free-up initrd memory in free_initrd_mem() instead
of doing nothing.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/kernel/setup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 9cd583b6d1cd..ed8dd28ca98c 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -97,8 +97,9 @@ static void __init setup_initrd(void)
 	initrd_end = 0;
 }
 
-void free_initrd_mem(unsigned long start, unsigned long end)
+void __init free_initrd_mem(unsigned long start, unsigned long end)
 {
+	free_reserved_area((void *)start, (void *)end, -1, "initrd");
 }
 #endif /* CONFIG_BLK_DEV_INITRD */
 
-- 
2.17.1