lkml.org 
[lkml]   [2018]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] dma: ste_dma40: Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this
switches to using a pre-allocated scratch register space, set up with
all other other allocations.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: dmaengine@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/dma/ste_dma40.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 1bc149af990e..f4edfc56f34e 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -555,6 +555,7 @@ struct d40_gen_dmac {
* @reg_val_backup_v4: Backup of registers that only exits on dma40 v3 and
* later
* @reg_val_backup_chan: Backup data for standard channel parameter registers.
+ * @regs_interrupt: Scratch space for registers during interrupt.
* @gcc_pwr_off_mask: Mask to maintain the channels that can be turned off.
* @gen_dmac: the struct for generic registers values to represent u8500/8540
* DMA controller
@@ -592,6 +593,7 @@ struct d40_base {
u32 reg_val_backup[BACKUP_REGS_SZ];
u32 reg_val_backup_v4[BACKUP_REGS_SZ_MAX];
u32 *reg_val_backup_chan;
+ u32 *regs_interrupt;
u16 gcc_pwr_off_mask;
struct d40_gen_dmac gen_dmac;
};
@@ -1637,7 +1639,7 @@ static irqreturn_t d40_handle_interrupt(int irq, void *data)
struct d40_chan *d40c;
unsigned long flags;
struct d40_base *base = data;
- u32 regs[base->gen_dmac.il_size];
+ u32 *regs = base->regs_interrupt;
struct d40_interrupt_lookup *il = base->gen_dmac.il;
u32 il_size = base->gen_dmac.il_size;

@@ -3258,13 +3260,22 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
if (!base->lcla_pool.alloc_map)
goto free_backup_chan;

+ base->regs_interrupt = kmalloc_array(base->gen_dmac.il_size,
+ sizeof(*base->regs_interrupt),
+ GFP_KERNEL);
+ if (!base->regs_interrupt)
+ goto free_map;
+
base->desc_slab = kmem_cache_create(D40_NAME, sizeof(struct d40_desc),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (base->desc_slab == NULL)
- goto free_map;
+ goto free_regs;
+

return base;
+ free_regs:
+ kfree(base->regs_interrupt);
free_map:
kfree(base->lcla_pool.alloc_map);
free_backup_chan:
--
2.17.1

--
Kees Cook
Pixel Security

\
 
 \ /
  Last update: 2018-06-29 20:52    [W:0.124 / U:3.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site