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Subject[PATCH v3] x86/setup: get ramdisk parameters only once
Date
The check and definitions related to ramdisk are similar in the
early_reserve_initrd() and reserve_initrd() functions. We can
get size and address of ramdisk in the setup_arch() and than
pass ramdisk structure with filled ramdisk related parameters
to early_reserve_initrd(), reserve_initrd() and relocate_initrd()
functions.

This allows us to not get ramdisk parameters from the bootparams
every time and save 59 bytes:

text data bss dec hex filename
9281618 5010736 15474688 29767042 1c63582 vmlinux.orig

text data bss dec hex filename
9281559 5010736 15474688 29766983 1c63547 vmlinux

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
---
Tested as with virtual machine as with real hardware.

Changelog:

v3: introduced ramdisk setup which is filled in th
setup_arch() and passed to the early_reserve_initrd()
and reserve_initrd().

v2: parameter of reserve_initrd() - int -> bool.
commit message updated.

arch/x86/kernel/setup.c | 92 +++++++++++++++++++++++++------------------------
1 file changed, 47 insertions(+), 45 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d3d80e6..c9d8a86 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -169,6 +169,14 @@ static struct resource bss_resource = {
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};

+/*
+ * ramdisk setup
+ */
+struct ramdisk {
+ u64 image;
+ u64 size;
+ u64 end;
+};

#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head.S */
@@ -318,12 +326,10 @@ static u64 __init get_ramdisk_size(void)
return ramdisk_size;
}

-static void __init relocate_initrd(void)
+static void __init relocate_initrd(struct ramdisk ramdisk)
{
/* Assume only end is not page aligned */
- u64 ramdisk_image = get_ramdisk_image();
- u64 ramdisk_size = get_ramdisk_size();
- u64 area_size = PAGE_ALIGN(ramdisk_size);
+ u64 area_size = PAGE_ALIGN(ramdisk.size);

/* We need to move the initrd down into directly mapped mem */
relocated_ramdisk = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
@@ -331,77 +337,60 @@ static void __init relocate_initrd(void)

if (!relocated_ramdisk)
panic("Cannot find place for new RAMDISK of size %lld\n",
- ramdisk_size);
+ ramdisk.size);

/* Note: this includes all the mem currently occupied by
the initrd, we rely on that fact to keep the data intact. */
memblock_reserve(relocated_ramdisk, area_size);
initrd_start = relocated_ramdisk + PAGE_OFFSET;
- initrd_end = initrd_start + ramdisk_size;
+ initrd_end = initrd_start + ramdisk.size;
printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
- relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
+ relocated_ramdisk, relocated_ramdisk + ramdisk.size - 1);

- copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
+ copy_from_early_mem((void *)initrd_start, ramdisk.image, ramdisk.size);

printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
" [mem %#010llx-%#010llx]\n",
- ramdisk_image, ramdisk_image + ramdisk_size - 1,
- relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
+ ramdisk.image, ramdisk.image + ramdisk.size - 1,
+ relocated_ramdisk, relocated_ramdisk + ramdisk.size - 1);
}

-static void __init early_reserve_initrd(void)
+static void __init early_reserve_initrd(struct ramdisk ramdisk)
{
- /* Assume only end is not page aligned */
- u64 ramdisk_image = get_ramdisk_image();
- u64 ramdisk_size = get_ramdisk_size();
- u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
-
- if (!boot_params.hdr.type_of_loader ||
- !ramdisk_image || !ramdisk_size)
- return; /* No initrd provided by bootloader */
-
- memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
+ memblock_reserve(ramdisk.image, ramdisk.end - ramdisk.image);
}
-static void __init reserve_initrd(void)
+static void __init reserve_initrd(struct ramdisk ramdisk)
{
- /* Assume only end is not page aligned */
- u64 ramdisk_image = get_ramdisk_image();
- u64 ramdisk_size = get_ramdisk_size();
- u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
u64 mapped_size;

- if (!boot_params.hdr.type_of_loader ||
- !ramdisk_image || !ramdisk_size)
- return; /* No initrd provided by bootloader */
-
initrd_start = 0;

mapped_size = memblock_mem_size(max_pfn_mapped);
- if (ramdisk_size >= (mapped_size>>1))
+ if (ramdisk.size >= (mapped_size>>1))
panic("initrd too large to handle, "
"disabling initrd (%lld needed, %lld available)\n",
- ramdisk_size, mapped_size>>1);
+ ramdisk.size, mapped_size>>1);

- printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
- ramdisk_end - 1);
+ printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk.image,
+ ramdisk.end - 1);

- if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
- PFN_DOWN(ramdisk_end))) {
+ if (pfn_range_is_mapped(PFN_DOWN(ramdisk.image),
+ PFN_DOWN(ramdisk.end))) {
/* All are mapped, easy case */
- initrd_start = ramdisk_image + PAGE_OFFSET;
- initrd_end = initrd_start + ramdisk_size;
+ initrd_start = ramdisk.image + PAGE_OFFSET;
+ initrd_end = initrd_start + ramdisk.size;
return;
}

- relocate_initrd();
+ relocate_initrd(ramdisk);

- memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
+ memblock_free(ramdisk.image, ramdisk.end - ramdisk.image);
}
#else
-static void __init early_reserve_initrd(void)
+static void __init early_reserve_initrd(struct ramdisk ramdisk)
{
}
-static void __init reserve_initrd(void)
+static void __init reserve_initrd(struct ramdisk ramdisk)
{
}
#endif /* CONFIG_BLK_DEV_INITRD */
@@ -844,13 +833,25 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
*
* Note: On x86_64, fixmaps are ready for use even before this is called.
*/
-
void __init setup_arch(char **cmdline_p)
{
+ struct ramdisk ramdisk_image = {
+ .image = get_ramdisk_image(),
+ .size = get_ramdisk_size(),
+ /* Assume only end is not page aligned */
+ .end = PAGE_ALIGN(ramdisk_image.image + ramdisk_image.size)
+ };
+ bool reserve_ramdisk = true;
+
memblock_reserve(__pa_symbol(_text),
(unsigned long)__bss_stop - (unsigned long)_text);

- early_reserve_initrd();
+ if (!boot_params.hdr.type_of_loader || !ramdisk_image.image
+ || !ramdisk_image.size) {
+ reserve_ramdisk = false;
+ return; /* No initrd provided by bootloader */
+ } else
+ early_reserve_initrd(ramdisk_image);

/*
* At this point everything still needed from the boot loader
@@ -1135,7 +1136,8 @@ void __init setup_arch(char **cmdline_p)
/* Allocate bigger log buffer */
setup_log_buf(1);

- reserve_initrd();
+ if (reserve_ramdisk)
+ reserve_initrd(ramdisk_image);

#if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);
--
2.7.0.25.gfc10eb5
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