diff options
Diffstat (limited to 'target/linux/airoha/patches-6.1/0004-ARM-9124-1-uncompress-Parse-linux-usable-memory-rang.patch')
| -rw-r--r-- | target/linux/airoha/patches-6.1/0004-ARM-9124-1-uncompress-Parse-linux-usable-memory-rang.patch | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/target/linux/airoha/patches-6.1/0004-ARM-9124-1-uncompress-Parse-linux-usable-memory-rang.patch b/target/linux/airoha/patches-6.1/0004-ARM-9124-1-uncompress-Parse-linux-usable-memory-rang.patch new file mode 100644 index 0000000000..0f0cbaa10f --- /dev/null +++ b/target/linux/airoha/patches-6.1/0004-ARM-9124-1-uncompress-Parse-linux-usable-memory-rang.patch @@ -0,0 +1,107 @@ +From 48342ae751c797ac73ac9c894b3f312df18ffd21 Mon Sep 17 00:00:00 2001 +From: Geert Uytterhoeven <geert+renesas@glider.be> +Date: Wed, 15 Sep 2021 13:46:20 +0100 +Subject: [PATCH] ARM: 9124/1: uncompress: Parse "linux,usable-memory-range" DT + property + +Add support for parsing the "linux,usable-memory-range" DT property. +This property is used to describe the usable memory reserved for the +crash dump kernel, and thus makes the memory reservation explicit. +If present, Linux no longer needs to mask the program counter, and rely +on the "mem=" kernel parameter to obtain the start and size of usable +memory. + +For backwards compatibility, the traditional method to derive the start +of memory is still used if "linux,usable-memory-range" is absent. + +Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> +Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> +Signed-off-by: Daniel Danzberger <daniel@dd-wrt.com> +--- + .../arm/boot/compressed/fdt_check_mem_start.c | 48 ++++++++++++++++--- + 1 file changed, 42 insertions(+), 6 deletions(-) + +--- a/arch/arm/boot/compressed/fdt_check_mem_start.c ++++ b/arch/arm/boot/compressed/fdt_check_mem_start.c +@@ -55,16 +55,17 @@ static uint64_t get_val(const fdt32_t *c + * DTB, and, if out-of-range, replace it by the real start address. + * To preserve backwards compatibility (systems reserving a block of memory + * at the start of physical memory, kdump, ...), the traditional method is +- * always used if it yields a valid address. ++ * used if it yields a valid address, unless the "linux,usable-memory-range" ++ * property is present. + * + * Return value: start address of physical memory to use + */ + uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt) + { +- uint32_t addr_cells, size_cells, base; ++ uint32_t addr_cells, size_cells, usable_base, base; + uint32_t fdt_mem_start = 0xffffffff; +- const fdt32_t *reg, *endp; +- uint64_t size, end; ++ const fdt32_t *usable, *reg, *endp; ++ uint64_t size, usable_end, end; + const char *type; + int offset, len; + +@@ -80,6 +81,27 @@ uint32_t fdt_check_mem_start(uint32_t me + if (addr_cells > 2 || size_cells > 2) + return mem_start; + ++ /* ++ * Usable memory in case of a crash dump kernel ++ * This property describes a limitation: memory within this range is ++ * only valid when also described through another mechanism ++ */ ++ usable = get_prop(fdt, "/chosen", "linux,usable-memory-range", ++ (addr_cells + size_cells) * sizeof(fdt32_t)); ++ if (usable) { ++ size = get_val(usable + addr_cells, size_cells); ++ if (!size) ++ return mem_start; ++ ++ if (addr_cells > 1 && fdt32_ld(usable)) { ++ /* Outside 32-bit address space */ ++ return mem_start; ++ } ++ ++ usable_base = fdt32_ld(usable + addr_cells - 1); ++ usable_end = usable_base + size; ++ } ++ + /* Walk all memory nodes and regions */ + for (offset = fdt_next_node(fdt, -1, NULL); offset >= 0; + offset = fdt_next_node(fdt, offset, NULL)) { +@@ -107,7 +129,20 @@ uint32_t fdt_check_mem_start(uint32_t me + + base = fdt32_ld(reg + addr_cells - 1); + end = base + size; +- if (mem_start >= base && mem_start < end) { ++ if (usable) { ++ /* ++ * Clip to usable range, which takes precedence ++ * over mem_start ++ */ ++ if (base < usable_base) ++ base = usable_base; ++ ++ if (end > usable_end) ++ end = usable_end; ++ ++ if (end <= base) ++ continue; ++ } else if (mem_start >= base && mem_start < end) { + /* Calculated address is valid, use it */ + return mem_start; + } +@@ -123,7 +158,8 @@ uint32_t fdt_check_mem_start(uint32_t me + } + + /* +- * The calculated address is not usable. ++ * The calculated address is not usable, or was overridden by the ++ * "linux,usable-memory-range" property. + * Use the lowest usable physical memory address from the DTB instead, + * and make sure this is a multiple of 2 MiB for phys/virt patching. + */ |