From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- arch/powerpc/boot/simpleboot.c | 87 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 arch/powerpc/boot/simpleboot.c (limited to 'arch/powerpc/boot/simpleboot.c') diff --git a/arch/powerpc/boot/simpleboot.c b/arch/powerpc/boot/simpleboot.c new file mode 100644 index 000000000..27591df41 --- /dev/null +++ b/arch/powerpc/boot/simpleboot.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * The simple platform -- for booting when firmware doesn't supply a device + * tree or any platform configuration information. + * All data is extracted from an embedded device tree + * blob. + * + * Authors: Scott Wood + * Grant Likely + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + * Copyright (c) 2008 Secret Lab Technologies Ltd. + */ + +#include "ops.h" +#include "types.h" +#include "io.h" +#include "stdio.h" +#include + +BSS_STACK(4*1024); + +extern int platform_specific_init(void) __attribute__((weak)); + +void platform_init(unsigned long r3, unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7) +{ + const u32 *na, *ns, *reg, *timebase; + u64 memsize64; + int node, size, i; + + /* Make sure FDT blob is sane */ + if (fdt_check_header(_dtb_start) != 0) + fatal("Invalid device tree blob\n"); + + /* Find the #address-cells and #size-cells properties */ + node = fdt_path_offset(_dtb_start, "/"); + if (node < 0) + fatal("Cannot find root node\n"); + na = fdt_getprop(_dtb_start, node, "#address-cells", &size); + if (!na || (size != 4)) + fatal("Cannot find #address-cells property"); + ns = fdt_getprop(_dtb_start, node, "#size-cells", &size); + if (!ns || (size != 4)) + fatal("Cannot find #size-cells property"); + + /* Find the memory range */ + node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type", + "memory", sizeof("memory")); + if (node < 0) + fatal("Cannot find memory node\n"); + reg = fdt_getprop(_dtb_start, node, "reg", &size); + if (size < (*na+*ns) * sizeof(u32)) + fatal("cannot get memory range\n"); + + /* Only interested in memory based at 0 */ + for (i = 0; i < *na; i++) + if (*reg++ != 0) + fatal("Memory range is not based at address 0\n"); + + /* get the memsize and truncate it to under 4G on 32 bit machines */ + memsize64 = 0; + for (i = 0; i < *ns; i++) + memsize64 = (memsize64 << 32) | *reg++; + if (sizeof(void *) == 4 && memsize64 >= 0x100000000ULL) + memsize64 = 0xffffffff; + + /* finally, setup the timebase */ + node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type", + "cpu", sizeof("cpu")); + if (node < 0) + fatal("Cannot find cpu node\n"); + timebase = fdt_getprop(_dtb_start, node, "timebase-frequency", &size); + if (timebase && (size == 4)) + timebase_period_ns = 1000000000 / *timebase; + + /* Now we have the memory size; initialize the heap */ + simple_alloc_init(_end, memsize64 - (unsigned long)_end, 32, 64); + + /* prepare the device tree and find the console */ + fdt_init(_dtb_start); + + if (platform_specific_init) + platform_specific_init(); + + serial_console_init(); +} -- cgit v1.3.1