diff options
author | Arnd Bergmann <arnd@arndb.de> | 2017-02-03 17:35:46 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-14 15:25:35 -0800 |
commit | 14cdf0f590447c4f7c5e1567ce73c81b2d9fe80b (patch) | |
tree | 358402c02ccc8e19e418b695965d1bc9d33c0f58 | |
parent | 6b10a704325a26d6f6495001e827b8601a170c3b (diff) |
hns: avoid stack overflow with CONFIG_KASAN
commit b3f2d07f4649adcf6905953a10d217b5683e4077 upstream.
The use of ACCESS_ONCE() looks like a micro-optimization to force gcc to use
an indexed load for the register address, but it has an absolutely detrimental
effect on builds with gcc-5 and CONFIG_KASAN=y, leading to a very likely
kernel stack overflow aside from very complex object code:
hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_update_stats':
hisilicon/hns/hns_dsaf_gmac.c:419:1: error: the frame size of 2912 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_reset_common':
hisilicon/hns/hns_dsaf_ppe.c:390:1: error: the frame size of 1184 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_get_regs':
hisilicon/hns/hns_dsaf_ppe.c:621:1: error: the frame size of 3632 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_common_regs':
hisilicon/hns/hns_dsaf_rcb.c:970:1: error: the frame size of 2784 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_get_regs':
hisilicon/hns/hns_dsaf_gmac.c:641:1: error: the frame size of 5728 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_ring_regs':
hisilicon/hns/hns_dsaf_rcb.c:1021:1: error: the frame size of 2208 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_comm_init':
hisilicon/hns/hns_dsaf_main.c:1209:1: error: the frame size of 1904 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_xgmac.c: In function 'hns_xgmac_get_regs':
hisilicon/hns/hns_dsaf_xgmac.c:748:1: error: the frame size of 4704 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_update_stats':
hisilicon/hns/hns_dsaf_main.c:2420:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_get_regs':
hisilicon/hns/hns_dsaf_main.c:2753:1: error: the frame size of 10768 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
This does not seem to happen any more with gcc-7, but removing the ACCESS_ONCE
seems safe anyway and it avoids a serious issue for some people. I have verified
that with gcc-5.3.1, the object code we get is better in the new version
both with and without CONFIG_KASAN, as we no longer allocate a 1344 byte
stack frame for hns_dsaf_get_regs() but otherwise have practically identical
object code.
With gcc-7.0.0, removing ACCESS_ONCE has no effect, the object code is already
good either way.
This patch is probably not urgent to get into 4.11 as only KASAN=y builds
with certain compilers are affected, but I still think it makes sense to
backport into older kernels.
Fixes: 511e6bc ("net: add Hisilicon Network Subsystem DSAF support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h index 878950a42e6c..2cf8b1d82d6a 100644 --- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h +++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_reg.h @@ -1007,9 +1007,7 @@ static inline void dsaf_write_reg(void __iomem *base, u32 reg, u32 value) { - u8 __iomem *reg_addr = ACCESS_ONCE(base); - - writel(value, reg_addr + reg); + writel(value, base + reg); } #define dsaf_write_dev(a, reg, value) \ @@ -1017,9 +1015,7 @@ static inline void dsaf_write_reg(void __iomem *base, u32 reg, u32 value) static inline u32 dsaf_read_reg(u8 __iomem *base, u32 reg) { - u8 __iomem *reg_addr = ACCESS_ONCE(base); - - return readl(reg_addr + reg); + return readl(base + reg); } static inline void dsaf_write_syscon(struct regmap *base, u32 reg, u32 value) |