[PATCH 5.17 334/772] x86/mm: Cleanup the control_va_addr_alignment() __setup handler

Greg Kroah-Hartman
2022-06-07T21:04:01Z

From: Randy Dunlap <rdunlap@infradead.org>

[ Upstream commit 1ef64b1e89e6d4018da46e08ffc32779a31160c7 ]

Clean up control_va_addr_alignment():

a. Make '=' required instead of optional (as documented).
b. Print a warning if an invalid option value is used.
c. Return 1 from the __setup handler when an invalid option value is
used. This prevents the kernel from polluting init's (limited)
environment space with the entire string.

Fixes: dfb09f9b7ab0 ("x86, amd: Avoid cache aliasing penalties on AMD family 15h")
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Link: https://lore.kernel.org/r/20220315001045.7680-1-rdunlap@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kernel/sys_x86_64.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 660b78827638..8cc653ffdccd 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -68,9 +68,6 @@ static int __init control_va_addr_alignment(char *str)
if (*str == 0)
return 1;

- if (*str == '=')
- str++;
-
if (!strcmp(str, "32"))
va_align.flags = ALIGN_VA_32;
else if (!strcmp(str, "64"))
@@ -80,11 +77,11 @@ static int __init control_va_addr_alignment(char *str)
else if (!strcmp(str, "on"))
va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
else
- return 0;
+ pr_warn("invalid option value: 'align_va_addr=%s'\n", str);

return 1;
}
-__setup("align_va_addr", control_va_addr_alignment);
+__setup("align_va_addr=", control_va_addr_alignment);

SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
--
2.35.1