diff options
Diffstat (limited to 'src/runtime/rt_start.S')
| -rw-r--r-- | src/runtime/rt_start.S | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/src/runtime/rt_start.S b/src/runtime/rt_start.S index ba1a975d7..aaf4ee59e 100644 --- a/src/runtime/rt_start.S +++ b/src/runtime/rt_start.S @@ -5,7 +5,7 @@ # # OpenPOWER HostBoot Project # -# Contributors Listed Below - COPYRIGHT 2013,2017 +# Contributors Listed Below - COPYRIGHT 2013,2019 # [+] International Business Machines Corp. # [+] Joel Stanley # @@ -52,13 +52,46 @@ _init: cmpwi cr0, r8, 0 # Perform relocations (if any). beq 2f + + # TLS workaround + # Load ASCII 'T','L','S' + 0x00 into bits 32:63 of r6, which will be used + # to compare against bits 0-31 of each relocation entry. A match signifies + # that this and the next relocation entry are the TLS module and offset + # relocations respectively. Skip both relocations before continuing the + # processing. These first two directives create the reference pattern to + # compare against. Also skip a relocation entry if its value is 0. + rldicl r6,r6,0,63 # Clear r6 to zero + addis r6, 0, 0x544C # Load ASCII "TL" into bits 32:47 of r6 + ori r6, r6, 0x5300 # Load ASCII "S" + 0x00 into bits 48:63 of r6 + mtctr r8 1: ldu r8, 8(r10) # Get relocation destination add r8, r8, r4 ld r7, 0(r8) # Get relocation address + + + # TLS workaround (continued for next 8 instructions) + rldicl r5,r5,0,63 # Clear r5 to zero + cmp cr0, 0, r5, r7 # Compare the relocation address (r7) to zero (r5) + beq cr0, 3f # If the relocation address is zero, do + # not adjust it and instead jump to the loop + # decrement/branch instruction + + rldicl r5,r7,32,32 # Rotate bits 0-31 of the relocation address + # into 32-63 and clear bits 0-31, saving result + # to r5, to set up the next comparison + cmp cr0, 0, r6, r5 # Compare bits 32-63, which should both contain + # ASCII TLS+0x00 if this is a TLS module + bne cr0, 4f # If not a TLS module relocation, keep going; + ldu r8, 8(r10) # otherwise, skip the TLS module relocation + bdnz 3f # and decrement the loop counter to match. Jump + # to a 2nd skip/decrement pair to effectively skip + # the next TLS module relocation as well +4: add r7, r7, r4 std r7, 0(r8) # Update relocation address. +3: bdnz 1b # Decrement CTR and continue loop. 2: addi r10, r4, 0x2008 # Find pointer to main TOC. |
