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drm/vc4: hdmi: Don't write past the end of a packet RAM slot #7579

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drm/vc4: hdmi: Don't write past the end of a packet RAM slot #7579

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5 changes: 4 additions & 1 deletion drivers/gpu/drm/vc4/vc4_hdmi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -654,7 +654,7 @@ static int vc4_hdmi_write_infoframe(struct drm_connector *connector,
if (!drm_dev_enter(drm, &idx))
return 0;

if (len > sizeof(buffer)) {
if (len > VC4_HDMI_PACKET_SIZE) {
ret = -ENOMEM;
goto out;
}
Expand All @@ -680,6 +680,9 @@ static int vc4_hdmi_write_infoframe(struct drm_connector *connector,
base + packet_reg);
packet_reg += 4;

if (packet_reg >= packet_reg_next)
break;

writel(buffer[i + 3] << 0 |
buffer[i + 4] << 8 |
buffer[i + 5] << 16 |
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6 changes: 6 additions & 0 deletions drivers/gpu/drm/vc4/vc4_hdmi_regs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,12 @@

#define VC4_HDMI_PACKET_STRIDE 0x24

/*
* A packet RAM slot is 9 words, holding a 3-byte packet header followed by
* four 7-byte subpackets, so only 31 of its 36 bytes are addressable.
*/
#define VC4_HDMI_PACKET_SIZE 31

enum vc4_hdmi_regs {
VC4_INVALID = 0,
VC4_HDMI,
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