drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

1 files changed, 178 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/powerpc.c b/drivers/misc/lkdtm/powerpc.c
new file mode 100644
index 000000000..6eaac79ea
--- /dev/null
+++ b/drivers/misc/lkdtm/powerpc.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "lkdtm.h"
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <asm/mmu.h>
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
+/* Inserts new slb entries */
+static void insert_slb_entry(unsigned long p, int ssize, int page_size)
+{
+	unsigned long flags;
+
+	flags = SLB_VSID_KERNEL | mmu_psize_defs[page_size].sllp;
+	preempt_disable();
+
+	asm volatile("slbmte %0,%1" :
+		     : "r" (mk_vsid_data(p, ssize, flags)),
+		       "r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED))
+		     : "memory");
+	isync();
+
+	asm volatile("slbmte %0,%1" :
+			: "r" (mk_vsid_data(p, ssize, flags)),
+			  "r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED + 1))
+			: "memory");
+	isync();
+
+	preempt_enable();
+}
+
+/* Inject slb multihit on vmalloc-ed address i.e 0xD00... */
+static int inject_vmalloc_slb_multihit(void)
+{
+	char *p;
+
+	p = vmalloc(PAGE_SIZE);
+	if (!p)
+		return -ENOMEM;
+
+	insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_vmalloc_psize);
+	/*
+	 * This triggers exception, If handled correctly we must recover
+	 * from this error.
+	 */
+	p[0] = '!';
+	vfree(p);
+	return 0;
+}
+
+/* Inject slb multihit on kmalloc-ed address i.e 0xC00... */
+static int inject_kmalloc_slb_multihit(void)
+{
+	char *p;
+
+	p = kmalloc(2048, GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_linear_psize);
+	/*
+	 * This triggers exception, If handled correctly we must recover
+	 * from this error.
+	 */
+	p[0] = '!';
+	kfree(p);
+	return 0;
+}
+
+/*
+ * Few initial SLB entries are bolted. Add a test to inject
+ * multihit in bolted entry 0.
+ */
+static void insert_dup_slb_entry_0(void)
+{
+	unsigned long test_address = PAGE_OFFSET, *test_ptr;
+	unsigned long esid, vsid;
+	unsigned long i = 0;
+
+	test_ptr = (unsigned long *)test_address;
+	preempt_disable();
+
+	asm volatile("slbmfee  %0,%1" : "=r" (esid) : "r" (i));
+	asm volatile("slbmfev  %0,%1" : "=r" (vsid) : "r" (i));
+
+	/* for i !=0 we would need to mask out the old entry number */
+	asm volatile("slbmte %0,%1" :
+			: "r" (vsid),
+			  "r" (esid | SLB_NUM_BOLTED)
+			: "memory");
+	isync();
+
+	asm volatile("slbmfee  %0,%1" : "=r" (esid) : "r" (i));
+	asm volatile("slbmfev  %0,%1" : "=r" (vsid) : "r" (i));
+
+	/* for i !=0 we would need to mask out the old entry number */
+	asm volatile("slbmte %0,%1" :
+			: "r" (vsid),
+			  "r" (esid | (SLB_NUM_BOLTED + 1))
+			: "memory");
+	isync();
+
+	pr_info("%s accessing test address 0x%lx: 0x%lx\n",
+		__func__, test_address, *test_ptr);
+
+	preempt_enable();
+}
+#endif /* CONFIG_PPC_64S_HASH_MMU */
+
+static __always_inline void tlbiel_va(unsigned long va,
+				      unsigned long pid,
+				      unsigned long ap,
+				      unsigned long ric)
+{
+	unsigned long rb, rs, prs, r;
+
+	rb = va & ~(PPC_BITMASK(52, 63));
+	rb |= ap << PPC_BITLSHIFT(58);
+	rs = pid << PPC_BITLSHIFT(31);
+
+	prs = 1; /* process scoped */
+	r = 1;   /* radix format */
+
+	/*
+	 * Trigger an MCE by issuing radix tlbiel with an invalid operand combination.
+	 * The combination of RIC = 2 with IS = 0 (Invalidation selector specified
+	 * in the RB register) is invalid.
+	 * This invalid combination causes hardware to raise a machine check.
+	 */
+	asm volatile(PPC_TLBIEL(%0, %4, %3, %2, %1)
+			: : "r"(rb), "i"(r), "i"(prs), "i"(ric), "r"(rs) : "memory");
+}
+
+static void lkdtm_PPC_SLB_MULTIHIT(void)
+{
+#ifdef CONFIG_PPC_64S_HASH_MMU
+	if (!radix_enabled()) {
+		pr_info("Injecting SLB multihit errors\n");
+		/*
+		 * These need not be separate tests, And they do pretty
+		 * much same thing. In any case we must recover from the
+		 * errors introduced by these functions, machine would not
+		 * survive these tests in case of failure to handle.
+		 */
+		inject_vmalloc_slb_multihit();
+		inject_kmalloc_slb_multihit();
+		insert_dup_slb_entry_0();
+		pr_info("Recovered from SLB multihit errors\n");
+	} else {
+		pr_err("XFAIL: This test is for ppc64 and with hash mode MMU only\n");
+	}
+#else
+	pr_err("XFAIL: This test requires CONFIG_PPC_64S_HASH_MMU\n");
+#endif
+}
+
+static void lkdtm_PPC_RADIX_TLBIEL(void)
+{
+	unsigned long addr = PAGE_OFFSET;
+
+	if (radix_enabled()) {
+		pr_info("Injecting Radix TLB invalidation MCE\n");
+		tlbiel_va(addr, 0, 0, RIC_FLUSH_ALL);
+		pr_info("Recovered from radix tlbiel attempt\n");
+	} else {
+		pr_err("XFAIL: This test is for ppc64 and with radix mode MMU only\n");
+	}
+}
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(PPC_SLB_MULTIHIT),
+	CRASHTYPE(PPC_RADIX_TLBIEL),
+};
+
+struct crashtype_category powerpc_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};