Replace legacy MMIO error injection with full PAPR-compliant RTAS error
injection supporting 14+ error types via
  - ibm,open-errinjct
  - ibm,errinjct
  - ibm,close-errinjct.

Key features:
- Complete open-session-inject-close cycle management
- Special handling for ibm,open-errinjct output format (token,status)
- Comprehensive buffer preparation per PAPR layouts
- All pr_* logging uses pr_fmt("EEH: ") prefix

Tested with corresponding QEMU patches:
https://lore.kernel.org/all/20251029150618.186803-1-nnmlinux@linux.ibm.com/ (local)

Signed-off-by: Narayana Murty N <redacted>
---
  arch/powerpc/platforms/pseries/eeh_pseries.c | 168 ++++++++++++++++---
  1 file changed, 147 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
index d6f2e0d43b89..6af2a153ec25 100644
--- a/arch/powerpc/platforms/pseries/eeh_pseries.c
+++ b/arch/powerpc/platforms/pseries/eeh_pseries.c

@@ -902,8 +902,7 @@ static int validate_special_event(unsigned long addr, unsigned long mask)
   * Return: 0 if valid, RTAS_INVALID_PARAMETER otherwise.
   */
  
-static int validate_corrupted_page(struct eeh_pe *pe __maybe_unused,
-				   unsigned long addr, unsigned long mask)
+static int validate_corrupted_page(unsigned long addr, unsigned long mask)
  {
  	if (!addr) {
  		pr_err("corrupted-page requires non-zero addr\n");

@@ -978,7 +977,7 @@ static int prepare_errinjct_buffer(struct eeh_pe *pe, int type, int func,
  		if (addr == 0)
  			return RTAS_INVALID_PARAMETER;
  
-		if (validate_corrupted_page(pe, addr, mask))
+		if (validate_corrupted_page(addr, mask))
  			return RTAS_INVALID_PARAMETER;
  
  		buf32[0] = cpu_to_be32(upper_32_bits(addr));

@@ -1047,6 +1046,97 @@ static int prepare_errinjct_buffer(struct eeh_pe *pe, int type, int func,
  	return 0;
  }
  
+/**
+ * rtas_open_errinjct_session - Open an RTAS error injection session
+ *
+ * Opens a session with the RTAS ibm,open-errinjct service.
+ *
+ * Return: Positive session token on success, negative error code on failure.

+}
+
+/**
+ * do_errinjct_call - Invoke the RTAS error injection service
+ * @errinjct_token: RTAS token for ibm,errinjct
+ * @type:           RTAS error type
+ * @session_token:  RTAS error injection session token
+ *
+ * Issues the RTAS ibm,errinjct call with the prepared work buffer. Logs errors
+ * on failure.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+
+static int do_errinjct_call(int errinjct_token, int type, int session_token)
+{
+	int rc, status;
+
+	if (errinjct_token == RTAS_UNKNOWN_SERVICE)
+		return -ENODEV;
+
+	/* errinjct takes: type, session_token, workbuf pointer (3 in), returns status */
+	rc = rtas_call(errinjct_token, 3, 1, &status, type, session_token,
+		       rtas_errinjct_buf);
+
+	if (rc || status != 0) {
+		pr_err("RTAS: errinjct failed: rc=%d, status=%d\n", rc, status);
+		return status ? status : -EIO;
+	}
+
+	pr_info("RTAS: errinjct ok: rc=%d, status=%d\n", rc, status);
+	return 0;
+}
+
  /**
   * pseries_eeh_err_inject - Inject specified error to the indicated PE
   * @pe: the indicated PE

@@ -1060,30 +1150,66 @@ static int prepare_errinjct_buffer(struct eeh_pe *pe, int type, int func,
  static int pseries_eeh_err_inject(struct eeh_pe *pe, int type, int func,
  				  unsigned long addr, unsigned long mask)
  {
-	struct	eeh_dev	*pdev;
+	int rc = 0;
+	int session_token = -1;
+	int errinjct_token;
  
-	/* Check on PCI error type */
-	if (type != EEH_ERR_TYPE_32 && type != EEH_ERR_TYPE_64)
-		return -EINVAL;
+	/* Validate type */
+	if (!validate_err_type(type)) {
+		pr_err("RTAS: invalid error type 0x%x\n", type);
+		return RTAS_INVALID_PARAMETER;
+	}
+	pr_debug("RTAS: error type 0x%x\n", type);
  
-	switch (func) {
-	case EEH_ERR_FUNC_LD_MEM_ADDR:
-	case EEH_ERR_FUNC_LD_MEM_DATA:
-	case EEH_ERR_FUNC_ST_MEM_ADDR:
-	case EEH_ERR_FUNC_ST_MEM_DATA:
-		/* injects a MMIO error for all pdev's belonging to PE */
-		pci_lock_rescan_remove();
-		list_for_each_entry(pdev, &pe->edevs, entry)
-			eeh_pe_inject_mmio_error(pdev->pdev);
-		pci_unlock_rescan_remove();
-		break;
-	default:
-		return -ERANGE;
+	/* For IOA bus errors we must validate err_func and addr/mask in PE.
+	 * For other types: if addr/mask present we'll still validate BAR range;
+	 * otherwise skip function checks.
+	 */
+	if (type == RTAS_ERR_TYPE_IOA_BUS_ERROR ||
+	    type == RTAS_ERR_TYPE_IOA_BUS_ERROR_64) {
+		/* Validate that addr/mask fall in the PE's BAR ranges */
+		rc = validate_addr_mask_in_pe(pe, addr, mask);
+		if (rc)
+			return rc;
+	} else if (addr || mask) {
+		/* If caller provided addr/mask for a non-IOA type, do a BAR check too */
+		rc = validate_addr_mask_in_pe(pe, addr, mask);
+		if (rc)
+			return rc;
  	}