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powerpc/spufs: fix copy_to_user while atomic
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Currently, we may perform a copy_to_user (through
simple_read_from_buffer()) while holding a context's register_lock,
while accessing the context save area.

This change uses a temporary buffer for the context save area data,
which we then pass to simple_read_from_buffer.

Includes changes from Christoph Hellwig <hch@lst.de>.

Fixes: bf1ab97 ("[POWERPC] coredump: Add SPU elf notes to coredump.")
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
[hch: renamed to function to avoid ___-prefixes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Jeremy Kerr authored and Al Viro committed May 5, 2020
1 parent 8f3d9f3 commit 88413a6
Showing 1 changed file with 75 additions and 38 deletions.
113 changes: 75 additions & 38 deletions arch/powerpc/platforms/cell/spufs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1978,8 +1978,9 @@ static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
int ret;
struct spu_context *ctx = file->private_data;
u32 stat, data;
int ret;

if (!access_ok(buf, len))
return -EFAULT;
Expand All @@ -1988,11 +1989,16 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
ret = __spufs_mbox_info_read(ctx, buf, len, pos);
stat = ctx->csa.prob.mb_stat_R;
data = ctx->csa.prob.pu_mb_R;
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

return ret;
/* EOF if there's no entry in the mbox */
if (!(stat & 0x0000ff))
return 0;

return simple_read_from_buffer(buf, len, pos, &data, sizeof(data));
}

static const struct file_operations spufs_mbox_info_fops = {
Expand All @@ -2019,6 +2025,7 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
u32 stat, data;
int ret;

if (!access_ok(buf, len))
Expand All @@ -2028,11 +2035,16 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
ret = __spufs_ibox_info_read(ctx, buf, len, pos);
stat = ctx->csa.prob.mb_stat_R;
data = ctx->csa.priv2.puint_mb_R;
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

return ret;
/* EOF if there's no entry in the ibox */
if (!(stat & 0xff0000))
return 0;

return simple_read_from_buffer(buf, len, pos, &data, sizeof(data));
}

static const struct file_operations spufs_ibox_info_fops = {
Expand All @@ -2041,6 +2053,11 @@ static const struct file_operations spufs_ibox_info_fops = {
.llseek = generic_file_llseek,
};

static size_t spufs_wbox_info_cnt(struct spu_context *ctx)
{
return (4 - ((ctx->csa.prob.mb_stat_R & 0x00ff00) >> 8)) * sizeof(u32);
}

static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
{
Expand All @@ -2049,7 +2066,7 @@ static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
u32 wbox_stat;

wbox_stat = ctx->csa.prob.mb_stat_R;
cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
cnt = spufs_wbox_info_cnt(ctx);
for (i = 0; i < cnt; i++) {
data[i] = ctx->csa.spu_mailbox_data[i];
}
Expand All @@ -2062,7 +2079,8 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
int ret;
u32 data[ARRAY_SIZE(ctx->csa.spu_mailbox_data)];
int ret, count;

if (!access_ok(buf, len))
return -EFAULT;
Expand All @@ -2071,11 +2089,13 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
ret = __spufs_wbox_info_read(ctx, buf, len, pos);
count = spufs_wbox_info_cnt(ctx);
memcpy(&data, &ctx->csa.spu_mailbox_data, sizeof(data));
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

return ret;
return simple_read_from_buffer(buf, len, pos, &data,
count * sizeof(u32));
}

static const struct file_operations spufs_wbox_info_fops = {
Expand All @@ -2084,27 +2104,33 @@ static const struct file_operations spufs_wbox_info_fops = {
.llseek = generic_file_llseek,
};

static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
static void spufs_get_dma_info(struct spu_context *ctx,
struct spu_dma_info *info)
{
struct spu_dma_info info;
struct mfc_cq_sr *qp, *spuqp;
int i;

info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
info->dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
info->dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
info->dma_info_status = ctx->csa.spu_chnldata_RW[24];
info->dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
info->dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
for (i = 0; i < 16; i++) {
qp = &info.dma_info_command_data[i];
spuqp = &ctx->csa.priv2.spuq[i];
struct mfc_cq_sr *qp = &info->dma_info_command_data[i];
struct mfc_cq_sr *spuqp = &ctx->csa.priv2.spuq[i];

qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
}
}

static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
{
struct spu_dma_info info;

spufs_get_dma_info(ctx, &info);

return simple_read_from_buffer(buf, len, pos, &info,
sizeof info);
Expand All @@ -2114,6 +2140,7 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
struct spu_dma_info info;
int ret;

if (!access_ok(buf, len))
Expand All @@ -2123,11 +2150,12 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
ret = __spufs_dma_info_read(ctx, buf, len, pos);
spufs_get_dma_info(ctx, &info);
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

return ret;
return simple_read_from_buffer(buf, len, pos, &info,
sizeof(info));
}

static const struct file_operations spufs_dma_info_fops = {
Expand All @@ -2136,32 +2164,39 @@ static const struct file_operations spufs_dma_info_fops = {
.llseek = no_llseek,
};

static void spufs_get_proxydma_info(struct spu_context *ctx,
struct spu_proxydma_info *info)
{
int i;

info->proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
info->proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
info->proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;

for (i = 0; i < 8; i++) {
struct mfc_cq_sr *qp = &info->proxydma_info_command_data[i];
struct mfc_cq_sr *puqp = &ctx->csa.priv2.puq[i];

qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
}
}

static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
char __user *buf, size_t len, loff_t *pos)
{
struct spu_proxydma_info info;
struct mfc_cq_sr *qp, *puqp;
int ret = sizeof info;
int i;

if (len < ret)
return -EINVAL;

if (!access_ok(buf, len))
return -EFAULT;

info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
for (i = 0; i < 8; i++) {
qp = &info.proxydma_info_command_data[i];
puqp = &ctx->csa.priv2.puq[i];

qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
}
spufs_get_proxydma_info(ctx, &info);

return simple_read_from_buffer(buf, len, pos, &info,
sizeof info);
Expand All @@ -2171,17 +2206,19 @@ static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
struct spu_context *ctx = file->private_data;
struct spu_proxydma_info info;
int ret;

ret = spu_acquire_saved(ctx);
if (ret)
return ret;
spin_lock(&ctx->csa.register_lock);
ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
spufs_get_proxydma_info(ctx, &info);
spin_unlock(&ctx->csa.register_lock);
spu_release_saved(ctx);

return ret;
return simple_read_from_buffer(buf, len, pos, &info,
sizeof(info));
}

static const struct file_operations spufs_proxydma_info_fops = {
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