drm/radeon: add locking around atombios scratch space usage

While developing MST support I noticed I often got the wrong data
back from a transaction, in a racy fashion. I noticed the scratch
space wasn't locked against concurrent users.

Based on a patch by Alex, but I've made it a bit more obvious when
things are locked.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Dave Airlie 2014-11-11 09:16:15 +10:00 committed by Alex Deucher
parent 03dca70852
commit 1c94984254
5 changed files with 19 additions and 3 deletions

View File

@ -1217,7 +1217,7 @@ free:
return ret;
}
int atom_execute_table(struct atom_context *ctx, int index, uint32_t * params)
int atom_execute_table_scratch_unlocked(struct atom_context *ctx, int index, uint32_t * params)
{
int r;
@ -1238,6 +1238,15 @@ int atom_execute_table(struct atom_context *ctx, int index, uint32_t * params)
return r;
}
int atom_execute_table(struct atom_context *ctx, int index, uint32_t * params)
{
int r;
mutex_lock(&ctx->scratch_mutex);
r = atom_execute_table_scratch_unlocked(ctx, index, params);
mutex_unlock(&ctx->scratch_mutex);
return r;
}
static int atom_iio_len[] = { 1, 2, 3, 3, 3, 3, 4, 4, 4, 3 };
static void atom_index_iio(struct atom_context *ctx, int base)

View File

@ -125,6 +125,7 @@ struct card_info {
struct atom_context {
struct card_info *card;
struct mutex mutex;
struct mutex scratch_mutex;
void *bios;
uint32_t cmd_table, data_table;
uint16_t *iio;
@ -145,6 +146,7 @@ extern int atom_debug;
struct atom_context *atom_parse(struct card_info *, void *);
int atom_execute_table(struct atom_context *, int, uint32_t *);
int atom_execute_table_scratch_unlocked(struct atom_context *, int, uint32_t *);
int atom_asic_init(struct atom_context *);
void atom_destroy(struct atom_context *);
bool atom_parse_data_header(struct atom_context *ctx, int index, uint16_t *size,

View File

@ -100,6 +100,7 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
memset(&args, 0, sizeof(args));
mutex_lock(&chan->mutex);
mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
base = (unsigned char *)(rdev->mode_info.atom_context->scratch + 1);
@ -113,7 +114,7 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
if (ASIC_IS_DCE4(rdev))
args.v2.ucHPD_ID = chan->rec.hpd;
atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
*ack = args.v1.ucReplyStatus;
@ -147,6 +148,7 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
r = recv_bytes;
done:
mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
mutex_unlock(&chan->mutex);
return r;

View File

@ -48,6 +48,7 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
memset(&args, 0, sizeof(args));
mutex_lock(&chan->mutex);
mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
base = (unsigned char *)rdev->mode_info.atom_context->scratch;
@ -82,7 +83,7 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
args.ucSlaveAddr = slave_addr << 1;
args.ucLineNumber = chan->rec.i2c_id;
atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
/* error */
if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
@ -95,6 +96,7 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
radeon_atom_copy_swap(buf, base, num, false);
done:
mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
mutex_unlock(&chan->mutex);
return r;

View File

@ -952,6 +952,7 @@ int radeon_atombios_init(struct radeon_device *rdev)
}
mutex_init(&rdev->mode_info.atom_context->mutex);
mutex_init(&rdev->mode_info.atom_context->scratch_mutex);
radeon_atom_initialize_bios_scratch_regs(rdev->ddev);
atom_allocate_fb_scratch(rdev->mode_info.atom_context);
return 0;