[PATCH 10/11] efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()

From: Matt Fleming
Date: Thu Jun 23 2016 - 07:35:51 EST


We can use the new efi_mem_reserve() API to mark the ESRT table as
reserved forever and save ourselves the trouble of copying the data
out into a kmalloc buffer.

The added advantage is that now the ESRT driver will work across
kexec reboot.

Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
Cc: Peter Jones <pjones@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/efi/esrt.c | 20 ++++----------------
1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index 75feb3f5829b..b93cd11f9bcc 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -235,7 +235,7 @@ static struct attribute_group esrt_attr_group = {
};

/*
- * remap the table, copy it to kmalloced pages, and unmap it.
+ * remap the table, validate it, mark it reserved and unmap it.
*/
void __init efi_esrt_init(void)
{
@@ -335,7 +335,7 @@ void __init efi_esrt_init(void)

end = esrt_data + size;
pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
- memblock_reserve(esrt_data, esrt_data_size);
+ efi_mem_reserve(esrt_data, esrt_data_size);

pr_debug("esrt-init: loaded.\n");
err_memunmap:
@@ -382,28 +382,18 @@ static void cleanup_entry_list(void)
static int __init esrt_sysfs_init(void)
{
int error;
- struct efi_system_resource_table __iomem *ioesrt;

pr_debug("esrt-sysfs: loading.\n");
if (!esrt_data || !esrt_data_size)
return -ENOSYS;

- ioesrt = ioremap(esrt_data, esrt_data_size);
- if (!ioesrt) {
+ esrt = ioremap(esrt_data, esrt_data_size);
+ if (!esrt) {
pr_err("ioremap(%pa, %zu) failed.\n", &esrt_data,
esrt_data_size);
return -ENOMEM;
}

- esrt = kmalloc(esrt_data_size, GFP_KERNEL);
- if (!esrt) {
- pr_err("kmalloc failed. (wanted %zu bytes)\n", esrt_data_size);
- iounmap(ioesrt);
- return -ENOMEM;
- }
-
- memcpy_fromio(esrt, ioesrt, esrt_data_size);
-
esrt_kobj = kobject_create_and_add("esrt", efi_kobj);
if (!esrt_kobj) {
pr_err("Firmware table registration failed.\n");
@@ -429,8 +419,6 @@ static int __init esrt_sysfs_init(void)
if (error)
goto err_cleanup_list;

- memblock_remove(esrt_data, esrt_data_size);
-
pr_debug("esrt-sysfs: loaded.\n");

return 0;
--
2.7.3