[PATCH v6 09/12] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter

[Jason Yan]

One may want to disable kaslr when boot, so provide a cmdline parameter
'nokaslr' to support this.

Signed-off-by: Jason Yan <yanaijie at huawei.com>
Cc: Diana Craciun <diana.craciun at nxp.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy at c-s.fr>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Paul Mackerras <paulus at samba.org>
Cc: Nicholas Piggin <npiggin at gmail.com>
Cc: Kees Cook <keescook at chromium.org>
Reviewed-by: Diana Craciun <diana.craciun at nxp.com>
Tested-by: Diana Craciun <diana.craciun at nxp.com>
Reviewed-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
 arch/powerpc/kernel/kaslr_booke.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
index 9a360b6124ed..fd32ae10c218 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -334,6 +334,11 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	return kaslr_offset;
 }
 
+static inline __init bool kaslr_disabled(void)
+{
+	return strstr(boot_command_line, "nokaslr") != NULL;
+}
+
 /*
  * To see if we need to relocate the kernel to a random offset
  * void *dt_ptr - address of the device tree
@@ -349,6 +354,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 	kernel_sz = (unsigned long)_end - KERNELBASE;
 
 	kaslr_get_cmdline(dt_ptr);
+	if (kaslr_disabled())
+		return;
 
 	offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
 
-- 
2.17.2