tpm: Cache all log related pointers in tpm_state

Move the tpm_state to RAM area and add all log related pointers
to it so they can be cached. Remove functions that previously
determined these pointers by searching for the TCPA ACPI table
and walking the log.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

1 files changed, 48 insertions, 62 deletions

diff --git a/src/tcgbios.c b/src/tcgbios.c
index 38bc737..018c580 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -90,10 +90,26 @@ typedef struct {
     u8            tpm_working:1;
     u8            if_shutdown:1;
     u8            tpm_driver_to_use:4;
+    struct tcpa_descriptor_rev2 *tcpa;
+
+    /* length of the TCPA log buffer */
+    u32           log_area_minimum_length;
+
+    /* start address of TCPA log buffer */
+    u8 *          log_area_start_address;
+
+    /* number of log entries written */
+    u32           entry_count;
+
+    /* address to write next log entry to */
+    u8 *          log_area_next_entry;
+
+    /* address of last entry written (need for TCG_StatusCheck) */
+    u8 *          log_area_last_entry;
 } tpm_state_t;
 
 
-static tpm_state_t tpm_state = {
+tpm_state_t tpm_state VARLOW = {
     .tpm_driver_to_use = TPM_INVALID_DRIVER,
 };
 
@@ -195,6 +211,10 @@ find_tcpa_by_rsdp(struct rsdp_descriptor *rsdp)
         ctr++;
     }
 
+    /* cache it */
+    if (tcpa)
+        tpm_state.tcpa = tcpa;
+
     return tcpa;
 }
 
@@ -205,6 +225,9 @@ find_tcpa_table(void)
     struct tcpa_descriptor_rev2 *tcpa = NULL;
     struct rsdp_descriptor *rsdp = RsdpAddr;
 
+    if (tpm_state.tcpa)
+        return tpm_state.tcpa;
+
     if (rsdp)
         tcpa = find_tcpa_by_rsdp(rsdp);
     else
@@ -240,11 +263,16 @@ get_lasa_base_ptr(u32 *log_area_minimum_length)
 static void
 reset_acpi_log(void)
 {
-    u32 log_area_minimum_length;
-    u8 *log_area_start_address = get_lasa_base_ptr(&log_area_minimum_length);
+    tpm_state.log_area_start_address =
+        get_lasa_base_ptr(&tpm_state.log_area_minimum_length);
+
+    if (tpm_state.log_area_start_address)
+        memset(tpm_state.log_area_start_address, 0,
+               tpm_state.log_area_minimum_length);
 
-    if (log_area_start_address)
-        memset(log_area_start_address, 0x0, log_area_minimum_length);
+    tpm_state.log_area_next_entry = tpm_state.log_area_start_address;
+    tpm_state.log_area_last_entry = NULL;
+    tpm_state.entry_count = 0;
 }
 
 
@@ -557,47 +585,6 @@ err_exit:
     tpm_set_failure();
 }
 
-static int
-is_valid_pcpes(struct pcpes *pcpes)
-{
-    return (pcpes->eventtype != 0);
-}
-
-
-static u8 *
-get_lasa_last_ptr(u16 *entry_count, u8 **log_area_start_address_next)
-{
-    struct pcpes *pcpes;
-    u32 log_area_minimum_length = 0;
-    u8 *log_area_start_address_base =
-        get_lasa_base_ptr(&log_area_minimum_length);
-    u8 *log_area_start_address_last = NULL;
-    u8 *end = log_area_start_address_base + log_area_minimum_length;
-    u32 size;
-
-    if (entry_count)
-        *entry_count = 0;
-
-    if (!log_area_start_address_base)
-        return NULL;
-
-    while (log_area_start_address_base < end) {
-        pcpes = (struct pcpes *)log_area_start_address_base;
-        if (!is_valid_pcpes(pcpes))
-            break;
-        if (entry_count)
-            (*entry_count)++;
-        size = pcpes->eventdatasize + offsetof(struct pcpes, event);
-        log_area_start_address_last = log_area_start_address_base;
-        log_area_start_address_base += size;
-    }
-
-    if (log_area_start_address_next)
-        *log_area_start_address_next = log_area_start_address_base;
-
-    return log_area_start_address_last;
-}
-
 /*
  * Extend the ACPI log with the given entry by copying the
  * entry data into the log.
@@ -615,20 +602,16 @@ tpm_extend_acpi_log(struct pcpes *pcpes,
                     const char *event, u32 event_length,
                     u16 *entry_count)
 {
-    u32 log_area_minimum_length, size;
-    u8 *log_area_start_address_base =
-        get_lasa_base_ptr(&log_area_minimum_length);
-    u8 *log_area_start_address_next = NULL;
+    u32 size;
 
     if (!has_working_tpm())
         return TCG_GENERAL_ERROR;
 
-    get_lasa_last_ptr(entry_count, &log_area_start_address_next);
+    dprintf(DEBUG_tcg, "TCGBIOS: LASA = %p, next entry = %p\n",
+            tpm_state.log_area_start_address, tpm_state.log_area_next_entry);
 
-    dprintf(DEBUG_tcg, "TCGBIOS: LASA_BASE = %p, LASA_NEXT = %p\n",
-            log_area_start_address_base, log_area_start_address_next);
+    if (tpm_state.log_area_next_entry == NULL) {
 
-    if (log_area_start_address_next == NULL || log_area_minimum_length == 0) {
         tpm_set_failure();
 
         return TCG_PC_LOGOVERFLOW;
@@ -636,8 +619,8 @@ tpm_extend_acpi_log(struct pcpes *pcpes,
 
     size = offsetof(struct pcpes, event) + event_length;
 
-    if ((log_area_start_address_next + size - log_area_start_address_base) >
-        log_area_minimum_length) {
+    if ((tpm_state.log_area_next_entry + size - tpm_state.log_area_start_address) >
+         tpm_state.log_area_minimum_length) {
         dprintf(DEBUG_tcg, "TCGBIOS: LOG OVERFLOW: size = %d\n", size);
 
         tpm_set_failure();
@@ -647,12 +630,16 @@ tpm_extend_acpi_log(struct pcpes *pcpes,
 
     pcpes->eventdatasize = event_length;
 
-    memcpy(log_area_start_address_next, pcpes, offsetof(struct pcpes, event));
-    memcpy(log_area_start_address_next + offsetof(struct pcpes, event),
+    memcpy(tpm_state.log_area_next_entry, pcpes, offsetof(struct pcpes, event));
+    memcpy(tpm_state.log_area_next_entry + offsetof(struct pcpes, event),
            event, event_length);
 
+    tpm_state.log_area_last_entry = tpm_state.log_area_next_entry;
+    tpm_state.log_area_next_entry += size;
+    tpm_state.entry_count++;
+
     if (entry_count)
-        (*entry_count)++;
+        *entry_count = tpm_state.entry_count;
 
     return 0;
 }
@@ -1013,9 +1000,8 @@ tpm_interrupt_handler32(struct bregs *regs)
             regs->ch = TCG_VERSION_MAJOR;
             regs->cl = TCG_VERSION_MINOR;
             regs->edx = 0x0;
-            regs->esi = (u32)get_lasa_base_ptr(NULL);
-            regs->edi =
-                  (u32)get_lasa_last_ptr(NULL, NULL);
+            regs->esi = (u32)tpm_state.log_area_start_address;
+            regs->edi = (u32)tpm_state.log_area_last_entry;
         }
         break;