[PATCH v9 5/8] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec

Chao Fan
2018-10-17T10:20:09Z

If KEXEC write the RSDP pointer to cmdline, parse the cmdline
and use it.
Imitate from early_param of "acpi_rsdp".

Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
---
arch/x86/boot/compressed/acpitb.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
index 50fa65cf824d..37b1f4407be8 100644
--- a/arch/x86/boot/compressed/acpitb.c
+++ b/arch/x86/boot/compressed/acpitb.c
@@ -8,6 +8,9 @@
#include <linux/numa.h>
#include <linux/acpi.h>

+#define STATIC
+#include <linux/decompress/mm.h>
+
/* Search EFI table for RSDP table. */
static void efi_get_rsdp_addr(acpi_physical_address *rsdp_addr)
{
@@ -200,3 +203,23 @@ static void bios_get_rsdp_addr(acpi_physical_address *rsdp_addr)
*rsdp_addr = (acpi_physical_address)address;
}
}
+
+static void get_acpi_rsdp(acpi_physical_address *rsdp_addr)
+{
+#ifdef CONFIG_KEXEC
+ unsigned long long res;
+ int len = 0;
+ char *val;
+
+ val = malloc(20);
+ len = cmdline_find_option("acpi_rsdp", val, 20);
+
+ if (len == -1)
+ return;
+
+ if (len > 0) {
+ val[len] = 0;
+ *rsdp_addr = (acpi_physical_address)kstrtoull(val, 0, &res);
+ }
+#endif
+}
--
2.17.2