Re: [U-Boot] [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-02-26 at 23:46 -0600, Bansal Aneesh-B39320 wrote:
Regards, Aneesh Bansal
-----Original Message----- From: Wood Scott-B07421 Sent: Friday, February 27, 2015 10:22 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-02-26 at 22:35 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, February 26, 2015 3:43 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
[Reposting comment on v4 as York requested]
On Wed, Feb 25, 2015 at 02:17:56PM +0530, Aneesh Bansal wrote:
diff --git a/arch/powerpc/cpu/mpc85xx/cpu_init.c b/arch/powerpc/cpu/mpc85xx/cpu_init.c index 4cf8853..ef56cc0 100644 --- a/arch/powerpc/cpu/mpc85xx/cpu_init.c +++ b/arch/powerpc/cpu/mpc85xx/cpu_init.c @@ -843,6 +843,23 @@ int cpu_init_r(void) setup_mp(); #endif
+#if defined(CONFIG_SYS_RAMBOOT) &&
defined(CONFIG_SYS_INIT_L3_ADDR) && \
- defined(CONFIG_SECURE_BOOT)
- /* Disable the TLB Created for L3 and create the TLB required for
* PCIE (CONFIG_SYS_PCIE1_MEM_VIRT) which was not createdearlier.
*/- int tlb_index;
- tlb_index = find_tlb_idx((void *)CONFIG_BPTR_VIRT_ADDR, 1);
- if (tlb_index != -1) {
disable_tlb(tlb_index);set_tlb(1, CONFIG_SYS_PCIE1_MEM_VIRT,CONFIG_SYS_PCIE1_MEM_PHYS,MAS3_SW|MAS3_SR, MAS2_I|MAS2_G,0, tlb_index, BOOKE_PAGESZ_1G, 1);- }
+#endif
Why are you assuming in generic 85xx code that the TLB for PCIE1 needs to be created? e500mc should have enough TLB1 entries that you don't need to share (or if it's due to address conflicts, a board may have PCI at a different address), and PCI may not exist at all on
some boards.
-Scott
TLB's are created in freescale/common/p_corenet/tlb.c
Which doesn't apply to all 85xx boards (even custom corenet-based boards might not use it -- or if that's not the case, it should be moved out of the board directory). It's also not obvious to anyone modifying that tlb.c file or the address of PCIE1 that this would be affected.
Note that on b4860qds, it's SRIO2_MEM_VIRT that conflicts with 0xbff00000, not PCIE1_MEM_VIRT.
In case of Secure Boot, L3 is used as 1M SRAM and the address of the
SRAM is at 0xbff00000.
Is this hardcoded into the silicon, or determined by PBI or something similar? If it's not hardcoded, can we choose a less problematic address?
It is not hardcoded but we have a restriction of choosing the address within 0 - 3.5G. 0xbff00000 seemed to be the least problematic at this point of time.
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes control.
If it is hardcoded, and we don't want to change the PCIE1 virtual address,
Actually it's PCIE2 that conflicts -- U-Boot just happens to use one big TLB entry to cover multiple PCIEs.
at least create defines for the entry to be created once SRAM goes away, rather than hardcoding PCIE1 here.
Are you suggesting something like this in cpu_init_r() set_tlb(1, CONFIG_SECBOOT_TLB_VIRT_ADDR, CONFIG_SECBOOT_TLB_PHYS_ADDR, CONFIG_SECBOOT_TLB_PERM, CONFIG_SECBOOT_TLB_ATTR, 0, tlb_index, CONFIG_SECBOOT_TLB_PAGESZ, 1);
If you can't remove the 3.5G limitation, yes.
I plan to define these macros in tlb.c where we have added the code for these TLBS creation
#define CONFIG_SECBOOT_TLB_VIRT_ADDR CONFIG_SYS_PCIE1_MEM_VIRT #define CONFIG_SECBOOT_TLB_PHYS_ADDR CONFIG_SYS_PCIE1_MEM_PHYS #define CONFIG_SECBOOT_TLB_PERM MAS3_SW|MAS3_SR #define CONFIG_SECBOOT_TLB_ATTR MAS2_I|MAS2_G #define CONFIG_SECBOOT_TLB_PAGESZ BOOKE_PAGESZ_1G
No, they are board-specific and need to be defined in the same place that the rest of the address map is defined (which I see you did in the v5 patch).
-Scott
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-02-26 at 23:46 -0600, Bansal Aneesh-B39320 wrote:
Regards, Aneesh Bansal
-----Original Message----- From: Wood Scott-B07421 Sent: Friday, February 27, 2015 10:22 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-02-26 at 22:35 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, February 26, 2015 3:43 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
[Reposting comment on v4 as York requested]
On Wed, Feb 25, 2015 at 02:17:56PM +0530, Aneesh Bansal wrote:
diff --git a/arch/powerpc/cpu/mpc85xx/cpu_init.c b/arch/powerpc/cpu/mpc85xx/cpu_init.c index 4cf8853..ef56cc0 100644 --- a/arch/powerpc/cpu/mpc85xx/cpu_init.c +++ b/arch/powerpc/cpu/mpc85xx/cpu_init.c @@ -843,6 +843,23 @@ int cpu_init_r(void) setup_mp(); #endif
+#if defined(CONFIG_SYS_RAMBOOT) &&
defined(CONFIG_SYS_INIT_L3_ADDR) && \
- defined(CONFIG_SECURE_BOOT)
- /* Disable the TLB Created for L3 and create the TLB required
for
* PCIE (CONFIG_SYS_PCIE1_MEM_VIRT) which was notcreated
earlier.
*/- int tlb_index;
- tlb_index = find_tlb_idx((void *)CONFIG_BPTR_VIRT_ADDR,
1);
- if (tlb_index != -1) {
disable_tlb(tlb_index);set_tlb(1, CONFIG_SYS_PCIE1_MEM_VIRT,CONFIG_SYS_PCIE1_MEM_PHYS,MAS3_SW|MAS3_SR, MAS2_I|MAS2_G,0, tlb_index, BOOKE_PAGESZ_1G, 1);- }
+#endif
Why are you assuming in generic 85xx code that the TLB for PCIE1 needs to be created? e500mc should have enough TLB1 entries that you don't need to share (or if it's due to address conflicts, a board may have PCI at a different address), and PCI may not exist at all on
some boards.
-Scott
TLB's are created in freescale/common/p_corenet/tlb.c
Which doesn't apply to all 85xx boards (even custom corenet-based boards might not use it -- or if that's not the case, it should be moved out of the board directory). It's also not obvious to anyone modifying that tlb.c file or the address of PCIE1 that this would be
affected.
Note that on b4860qds, it's SRIO2_MEM_VIRT that conflicts with 0xbff00000, not PCIE1_MEM_VIRT.
This is taken care now in v5, where we have defined the addresses in corenet_ds.h. So this will not impact other platforms like B4860.
In case of Secure Boot, L3 is used as 1M SRAM and the address of the
SRAM is at 0xbff00000.
Is this hardcoded into the silicon, or determined by PBI or something
similar?
If it's not hardcoded, can we choose a less problematic address?
It is not hardcoded but we have a restriction of choosing the address within
0 - 3.5G.
0xbff00000 seemed to be the least problematic at this point of time.
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
If it is hardcoded, and we don't want to change the PCIE1 virtual address,
Actually it's PCIE2 that conflicts -- U-Boot just happens to use one big TLB entry to cover multiple PCIEs.
at least create defines for the entry to be created once SRAM goes away, rather than hardcoding PCIE1 here.
Are you suggesting something like this in cpu_init_r() set_tlb(1, CONFIG_SECBOOT_TLB_VIRT_ADDR, CONFIG_SECBOOT_TLB_PHYS_ADDR, CONFIG_SECBOOT_TLB_PERM, CONFIG_SECBOOT_TLB_ATTR, 0, tlb_index, CONFIG_SECBOOT_TLB_PAGESZ, 1);
If you can't remove the 3.5G limitation, yes.
I plan to define these macros in tlb.c where we have added the code for these TLBS creation
#define CONFIG_SECBOOT_TLB_VIRT_ADDR
CONFIG_SYS_PCIE1_MEM_VIRT
#define CONFIG_SECBOOT_TLB_PHYS_ADDR
CONFIG_SYS_PCIE1_MEM_PHYS
#define CONFIG_SECBOOT_TLB_PERM MAS3_SW|MAS3_SR #define CONFIG_SECBOOT_TLB_ATTR MAS2_I|MAS2_G #define CONFIG_SECBOOT_TLB_PAGESZ BOOKE_PAGESZ_1G
No, they are board-specific and need to be defined in the same place that the rest of the address map is defined (which I see you did in the v5 patch).
-Scott
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes
control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following: 1. PBI Commands to configure CPC as SRAM with address 0xBFF0_0000. 2. Compile U-boot with TEXT BASE as 0xFFF40000. 3. Copy the U-boot from NAND via PBI commands to CPC (SRAM) on address 0xBFF4_0000 4. The BootROM will validate the U-boot and transfer the control to 0xBFFF_FFFC. 5. When U-boot is executing, then in the last 4K code, when shifting from AS=0 to AS=1, we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000. (Similar to what is done for NOR Boot)
- Aneesh
On Tue, 2015-03-10 at 03:50 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes
control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following:
- PBI Commands to configure CPC as SRAM with address 0xBFF0_0000.
- Compile U-boot with TEXT BASE as 0xFFF40000.
- Copy the U-boot from NAND via PBI commands to CPC (SRAM) on address 0xBFF4_0000
- The BootROM will validate the U-boot and transfer the control to 0xBFFF_FFFC.
- When U-boot is executing, then in the last 4K code, when shifting from AS=0 to AS=1, we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000. (Similar to what is done for NOR Boot)
Something like that, except in step 5 it would only be changing the virtual address, not the physical address (unless you can do a similar trick as NOR does, to have the L3 cache repeat and cover both addresses at once).
-Scott
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 10:34 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 03:50 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes
control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following:
- PBI Commands to configure CPC as SRAM with address 0xBFF0_0000.
- Compile U-boot with TEXT BASE as 0xFFF40000.
- Copy the U-boot from NAND via PBI commands to CPC (SRAM) on
address 0xBFF4_0000 4. The BootROM will validate the U-boot and transfer
the control to 0xBFFF_FFFC.
- When U-boot is executing, then in the last 4K code, when shifting from
AS=0 to AS=1,
we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000.(Similar to what is done for NOR Boot)
Something like that, except in step 5 it would only be changing the virtual address, not the physical address (unless you can do a similar trick as NOR does, to have the L3 cache repeat and cover both addresses at once).
-Scott
The problems that I see here are: 1. Can SRAM address be changed without disabling and re-configuring CPC as SRAM ? 2. Assuming that above is possible,
We are executing from CPC configured as SRAM with address as 0xBFF0_0000. (Because of 3.5 G Limitation) We create a LAW for 0xFFF0_0000 to map to CPC and change the address of SRAM in CPC controller from BFF0_0000 to 0xFFF0_0000. (If it is possible... need to check this) But now the Code which was executing is executing from 0xBFFx_xxxx. So the CPC controller will reject this since configured address for SRAM is different. NOR can have two addresses as IFC controller ignores the upper bit but this is not possible with CPC.
To avoid this, even if we create a TLB Entry to map the virtual address 0xBFFx_xxxx to 0xFFFx_xxxx, then we have a race condition. Which step to do first? Creation of TLB entry or changing the address of SRAM in CPC controller. Because the current execution PC is 0xBFFx_xxxx (CPC as SRAM)
-Aneesh
On Tue, 2015-03-10 at 12:52 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 10:34 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 03:50 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 2:41 AM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
Where does the 3.5G limitation come from? Even if the physical address needs to be elsewhere due to bootrom constraints, we should be able to map it wherever we want in the TLB once U-Boot takes
control.
The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following:
- PBI Commands to configure CPC as SRAM with address 0xBFF0_0000.
- Compile U-boot with TEXT BASE as 0xFFF40000.
- Copy the U-boot from NAND via PBI commands to CPC (SRAM) on
address 0xBFF4_0000 4. The BootROM will validate the U-boot and transfer
the control to 0xBFFF_FFFC.
- When U-boot is executing, then in the last 4K code, when shifting from
AS=0 to AS=1,
we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000.(Similar to what is done for NOR Boot)
Something like that, except in step 5 it would only be changing the virtual address, not the physical address (unless you can do a similar trick as NOR does, to have the L3 cache repeat and cover both addresses at once).
-Scott
The problems that I see here are:
- Can SRAM address be changed without disabling and re-configuring CPC as SRAM ?
Again, I'm only talking about changing the virtual address.
- Assuming that above is possible,
We are executing from CPC configured as SRAM with address as 0xBFF0_0000. (Because of 3.5 G Limitation) We create a LAW for 0xFFF0_0000 to map to CPC and change the address of SRAM in CPC controller from BFF0_0000 to 0xFFF0_0000. (If it is possible... need to check this) But now the Code which was executing is executing from 0xBFFx_xxxx. So the CPC controller will reject this since configured address for SRAM is different. NOR can have two addresses as IFC controller ignores the upper bit but this is not possible with CPC.
...and this is why.
To avoid this, even if we create a TLB Entry to map the virtual address 0xBFFx_xxxx to 0xFFFx_xxxx, then we have a race condition. Which step to do first?
Why is there a race condition? You can have two virtual addresses pointing at the same physical address.
-Scott
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 11:29 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 12:52 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 10:34 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 03:50 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote:
> -----Original Message----- > From: Wood Scott-B07421 > Sent: Thursday, March 05, 2015 2:41 AM > To: Bansal Aneesh-B39320 > Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta > Ruchika-R66431 > Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- > NAND secure boot target for P3041 > > Where does the 3.5G limitation come from? Even if the > physical address needs to be elsewhere due to bootrom > constraints, we should be able to map it wherever we want in > the TLB once U-Boot takes
control.
> The 3.5G limitation comes from BootROM in case of secure Boot. Initially U-Boot has to run from CPC configured as SRAM with address Within 3.5G. Once U-boot has relocated to DDR, we have removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following:
- PBI Commands to configure CPC as SRAM with address 0xBFF0_0000.
- Compile U-boot with TEXT BASE as 0xFFF40000.
- Copy the U-boot from NAND via PBI commands to CPC (SRAM) on
address 0xBFF4_0000 4. The BootROM will validate the U-boot and transfer
the control to 0xBFFF_FFFC.
- When U-boot is executing, then in the last 4K code, when
shifting from
AS=0 to AS=1,
we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000.(Similar to what is done for NOR Boot)
Something like that, except in step 5 it would only be changing the virtual address, not the physical address (unless you can do a similar trick as NOR does, to have the L3 cache repeat and cover both
addresses at once).
-Scott
The problems that I see here are:
- Can SRAM address be changed without disabling and re-configuring CPC
as SRAM ?
Again, I'm only talking about changing the virtual address.
If we just change the virtual address to 0xFFF0_0000, how will it work? The SRAM address configured in CPC controller is 0xBFF0_0000. So, won't the CPC controller reject fetches with address 0xFFFx_xxxx.
- Assuming that above is possible,
We are executing from CPC configured as SRAM with address as 0xBFF0_0000. (Because of 3.5 G Limitation) We create a LAW for 0xFFF0_0000 to map to CPC and change the address of SRAM in CPC controller from BFF0_0000 to 0xFFF0_0000. (If it is possible... need to check
this) But now the Code which was executing is executing from 0xBFFx_xxxx. So the CPC controller will reject this since configured address for SRAM is different.
NOR can have two addresses as IFC controller ignores the upper bit but this
is not possible with CPC.
...and this is why.
To avoid this, even if we create a TLB Entry to map the virtual address
0xBFFx_xxxx to 0xFFFx_xxxx, then we have a race condition. Which step to do first?
Why is there a race condition? You can have two virtual addresses pointing at the same physical address.
We can have two virtual addresses pointing to same physical address but we can't have two addresses for SRAM in CPC controller. CPC controller will accept fetches with only one address 0xBFFx_xxxx or 0xFFFx_xxxx. This is not a problem with NOR because IFC controller neglects the upper bits in address and hence having two virtual address was not an issue.
The code is currently executing from PC 0xBFFx_xxxx and CPC is configured with SRAM address 0xBFFx_xxxx. If SRAM address in CPC is changed to 0xFFFx_xxxx before creation of TLB entry for virtual address 0xFFFx_xxxx, Then the CPC controller will reject fetches for address 0xBFFx_xxxx when PC moves to next instruction.
If TLB entry is created to change the virtual address to 0xFFFx_xxxx, then CPC being still configured with address 0xBFFx_xxxx will reject fetches for address 0xFFFx_xxxx.
-Scott
On Tue, 2015-03-10 at 13:27 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 11:29 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 12:52 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Tuesday, March 10, 2015 10:34 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431; Kushwaha Prabhakar-B32579 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Tue, 2015-03-10 at 03:50 -0500, Bansal Aneesh-B39320 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: Thursday, March 05, 2015 10:38 PM To: Bansal Aneesh-B39320 Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta Ruchika-R66431 Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- NAND secure boot target for P3041
On Thu, 2015-03-05 at 01:26 -0600, Bansal Aneesh-B39320 wrote: > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Thursday, March 05, 2015 2:41 AM > > To: Bansal Aneesh-B39320 > > Cc: u-boot@lists.denx.de; Sun York-R58495; Gupta > > Ruchika-R66431 > > Subject: Re: [U-Boot, 1/2, v4] powerpc/mpc85xx: SECURE BOOT- > > NAND secure boot target for P3041 > > > > Where does the 3.5G limitation come from? Even if the > > physical address needs to be elsewhere due to bootrom > > constraints, we should be able to map it wherever we want in > > the TLB once U-Boot takes control. > > > The 3.5G limitation comes from BootROM in case of secure Boot. > Initially U-Boot has to run from CPC configured as SRAM with > address Within 3.5G. Once U-boot has relocated to DDR, we have > removed the Corresponding TLB entry.
Again, you could relocate the virtual address of L3 much earlier.
-Scott
Are you suggesting the following:
- PBI Commands to configure CPC as SRAM with address 0xBFF0_0000.
- Compile U-boot with TEXT BASE as 0xFFF40000.
- Copy the U-boot from NAND via PBI commands to CPC (SRAM) on
address 0xBFF4_0000 4. The BootROM will validate the U-boot and transfer
the control to 0xBFFF_FFFC.
- When U-boot is executing, then in the last 4K code, when
shifting from
AS=0 to AS=1,
we change the address of SRAM from 0xBFF0_0000 to 0xFFF0_0000.(Similar to what is done for NOR Boot)
Something like that, except in step 5 it would only be changing the virtual address, not the physical address (unless you can do a similar trick as NOR does, to have the L3 cache repeat and cover both
addresses at once).
-Scott
The problems that I see here are:
- Can SRAM address be changed without disabling and re-configuring CPC
as SRAM ?
Again, I'm only talking about changing the virtual address.
If we just change the virtual address to 0xFFF0_0000, how will it work? The SRAM address configured in CPC controller is 0xBFF0_0000. So, won't the CPC controller reject fetches with address 0xFFFx_xxxx.
It's a virtual address. The CPC will never see it.
Why is there a race condition? You can have two virtual addresses pointing at the same physical address.
We can have two virtual addresses pointing to same physical address but we can't have two addresses for SRAM in CPC controller.
And you don't need to.
-Scott
participants (2)
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aneesh.bansal＠freescale.com -
Scott Wood