Thread (27 messages) 27 messages, 2 authors, 2019-08-08

Lifecycle

  1. Posted Jason Yan <yanaijie@huawei.com>
  2. Reviewed-by Diana Craciun
  3. Tested-by Diana Craciun

[PATCH v5 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter

From: Jason Yan <yanaijie@huawei.com>
Date: 2019-08-07 06:40:21
Also in: lkml
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

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

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Diana Craciun <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <redacted>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <redacted>
Reviewed-by: Diana Craciun <redacted>
Tested-by: Diana Craciun <redacted>
Reviewed-by: Christophe Leroy <redacted>
---
 arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
index c6b326424b54..436f9a03f385 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -361,6 +361,18 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	return kaslr_offset;
 }
 
+static inline __init bool kaslr_disabled(void)
+{
+	char *str;
+
+	str = strstr(boot_command_line, "nokaslr");
+	if (str == boot_command_line ||
+	    (str > boot_command_line && *(str - 1) == ' '))
+		return true;
+
+	return false;
+}
+
 /*
  * To see if we need to relocate the kernel to a random offset
  * void *dt_ptr - address of the device tree
@@ -376,6 +388,8 @@ 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
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