On Fri, Jun 16, 2023 at 04:48:47PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > In some configurations, gcc decides not to inline the register accessor functions, > which in turn leads to lots of temporary hantro_reg structures on the stack that > cannot be eliminated because they escape into an uninlined function: > > drivers/media/platform/verisilicon/rockchip_vpu981_hw_av1_dec.c:1022:1: warning: the frame size of 1112 bytes is larger than 1024 bytes [-Wframe-larger-than=] > > Mark all of these as __always_inline so the compiler is able to completely > eliminate the temporary structures instead, which brings the stack usage > back down to just the normal local variables. > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-kbuild-all/202306151506.goHEegOd-lkp@xxxxxxxxx/ > Fixes: 727a400686a2c ("media: verisilicon: Add Rockchip AV1 decoder") > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> For what it's worth, this patch massively helps with avoiding a warning with clang 16.x and older, for presumably a similar reason, since this happens with allmodconfig, which turns on a bunch of sanitizers. https://github.com/ClangBuiltLinux/linux/issues/1875 Before this change: drivers/media/platform/verisilicon/rockchip_vpu981_hw_av1_dec.c:2097:5: error: stack frame size (2096) exceeds limit (2048) in 'rockchip_vpu981_av1_dec_run' [-Werror,-Wframe-larger-than] int rockchip_vpu981_av1_dec_run(struct hantro_ctx *ctx) ^ 238/2096 (11.35%) spills, 1858/2096 (88.65%) variables After this change: drivers/media/platform/verisilicon/rockchip_vpu981_hw_av1_dec.c:2097:5: error: stack frame size (496) exceeds limit (200) in 'rockchip_vpu981_av1_dec_run' [-Werror,-Wframe-larger-than] int rockchip_vpu981_av1_dec_run(struct hantro_ctx *ctx) ^ 265/496 (53.43%) spills, 231/496 (46.57%) variables If this could be picked up either before the 6.5 media pull goes out or at some point during the -rc cycle, that would be great! Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx> > --- > drivers/media/platform/verisilicon/hantro.h | 22 ++++++++++----------- > 1 file changed, 11 insertions(+), 11 deletions(-) > > diff --git a/drivers/media/platform/verisilicon/hantro.h b/drivers/media/platform/verisilicon/hantro.h > index 6523ffb748812..6c5e56ce5b351 100644 > --- a/drivers/media/platform/verisilicon/hantro.h > +++ b/drivers/media/platform/verisilicon/hantro.h > @@ -370,26 +370,26 @@ extern int hantro_debug; > pr_err("%s:%d: " fmt, __func__, __LINE__, ##args) > > /* Structure access helpers. */ > -static inline struct hantro_ctx *fh_to_ctx(struct v4l2_fh *fh) > +static __always_inline struct hantro_ctx *fh_to_ctx(struct v4l2_fh *fh) > { > return container_of(fh, struct hantro_ctx, fh); > } > > /* Register accessors. */ > -static inline void vepu_write_relaxed(struct hantro_dev *vpu, > +static __always_inline void vepu_write_relaxed(struct hantro_dev *vpu, > u32 val, u32 reg) > { > vpu_debug(6, "0x%04x = 0x%08x\n", reg / 4, val); > writel_relaxed(val, vpu->enc_base + reg); > } > > -static inline void vepu_write(struct hantro_dev *vpu, u32 val, u32 reg) > +static __always_inline void vepu_write(struct hantro_dev *vpu, u32 val, u32 reg) > { > vpu_debug(6, "0x%04x = 0x%08x\n", reg / 4, val); > writel(val, vpu->enc_base + reg); > } > > -static inline u32 vepu_read(struct hantro_dev *vpu, u32 reg) > +static __always_inline u32 vepu_read(struct hantro_dev *vpu, u32 reg) > { > u32 val = readl(vpu->enc_base + reg); > > @@ -397,27 +397,27 @@ static inline u32 vepu_read(struct hantro_dev *vpu, u32 reg) > return val; > } > > -static inline void vdpu_write_relaxed(struct hantro_dev *vpu, > +static __always_inline void vdpu_write_relaxed(struct hantro_dev *vpu, > u32 val, u32 reg) > { > vpu_debug(6, "0x%04x = 0x%08x\n", reg / 4, val); > writel_relaxed(val, vpu->dec_base + reg); > } > > -static inline void vdpu_write(struct hantro_dev *vpu, u32 val, u32 reg) > +static __always_inline void vdpu_write(struct hantro_dev *vpu, u32 val, u32 reg) > { > vpu_debug(6, "0x%04x = 0x%08x\n", reg / 4, val); > writel(val, vpu->dec_base + reg); > } > > -static inline void hantro_write_addr(struct hantro_dev *vpu, > +static __always_inline void hantro_write_addr(struct hantro_dev *vpu, > unsigned long offset, > dma_addr_t addr) > { > vdpu_write(vpu, addr & 0xffffffff, offset); > } > > -static inline u32 vdpu_read(struct hantro_dev *vpu, u32 reg) > +static __always_inline u32 vdpu_read(struct hantro_dev *vpu, u32 reg) > { > u32 val = readl(vpu->dec_base + reg); > > @@ -425,7 +425,7 @@ static inline u32 vdpu_read(struct hantro_dev *vpu, u32 reg) > return val; > } > > -static inline u32 vdpu_read_mask(struct hantro_dev *vpu, > +static __always_inline u32 vdpu_read_mask(struct hantro_dev *vpu, > const struct hantro_reg *reg, > u32 val) > { > @@ -437,14 +437,14 @@ static inline u32 vdpu_read_mask(struct hantro_dev *vpu, > return v; > } > > -static inline void hantro_reg_write(struct hantro_dev *vpu, > +static __always_inline void hantro_reg_write(struct hantro_dev *vpu, > const struct hantro_reg *reg, > u32 val) > { > vdpu_write_relaxed(vpu, vdpu_read_mask(vpu, reg, val), reg->base); > } > > -static inline void hantro_reg_write_s(struct hantro_dev *vpu, > +static __always_inline void hantro_reg_write_s(struct hantro_dev *vpu, > const struct hantro_reg *reg, > u32 val) > { > -- > 2.39.2 >
