Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
Hi Bryan, On 18 April 2018 at 11:22, Bryan O'Donoghue wrote: > > > > On 17/04/18 23:21, Simon Glass wrote: >> >> Hi Bryan, >> >> On 17 April 2018 at 03:27, Bryan O'Donoghue >> wrote: >>> >>> >>> >>> >>> On 16/04/18 17:49, Simon Glass wrote: On 15 April 2018 at 04:48, Bryan O'Donoghue wrote: > > > commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") > aligns the end address of the cache flush operation to a cache-line size > to > ensure lower-layers in the code accept the range provided and flush. > > A similar action should be taken for the begin address of a cache flush > operation. The load address may not be aligned to a cache-line boundary, > so > ensure the passed address is aligned. > > Signed-off-by: Bryan O'Donoghue > Reported-by: Breno Matheus Lima > Suggested-by: Tom Rini > Cc: Simon Glass > --- >common/bootm.c | 8 +++- >1 file changed, 7 insertions(+), 1 deletion(-) I feel that using an unaligned start address should probably be an error. Why would that be useful? Apart from that: Reviewed-by: Simon Glass Regards, Simon >>> >>> We are booting a kernel that has an entry point aligned a cacheline >>> boundary with a header prefix/load-address that is a negative offset from >>> that. >>> >>> We could go about trying to move the load/ep address of that kernel but, my >>> feeling is that's probably the wrong thing to do, we can just as easily >>> align-down and add to the flush length. >> >> >> What header is this? Perhaps it should be updated to be a cache-line >> multiple in size? > > > I don't think so it's a TEE header, that's pretty fixed. > >> I suspect the impact of this patch is minimal, since people hopefully >> don't put data just before the image is loaded. But if they did, and >> the image is loaded using DMA behind the cache, we might have tricky >> bugs. That's why in general I'm not keen on silently messing with the >> cache outside the expected range. > > > Yes, I agree with both points. > > How printing a warning ? > > if (flush_start < load) > flush_len += load - flush_start; > > if (flush_start < load) { > printf("WARNING: unaligned load address 0x%08lx flushing 0x%08lx\n", >load, flush_start); > > flush_len += load - flush_start; > } That seems like a good idea. Regards, Simon ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
On 17/04/18 23:21, Simon Glass wrote: Hi Bryan, On 17 April 2018 at 03:27, Bryan O'Donoghue wrote: On 16/04/18 17:49, Simon Glass wrote: On 15 April 2018 at 04:48, Bryan O'Donoghue wrote: commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") aligns the end address of the cache flush operation to a cache-line size to ensure lower-layers in the code accept the range provided and flush. A similar action should be taken for the begin address of a cache flush operation. The load address may not be aligned to a cache-line boundary, so ensure the passed address is aligned. Signed-off-by: Bryan O'Donoghue Reported-by: Breno Matheus Lima Suggested-by: Tom Rini Cc: Simon Glass --- common/bootm.c | 8 +++- 1 file changed, 7 insertions(+), 1 deletion(-) I feel that using an unaligned start address should probably be an error. Why would that be useful? Apart from that: Reviewed-by: Simon Glass Regards, Simon We are booting a kernel that has an entry point aligned a cacheline boundary with a header prefix/load-address that is a negative offset from that. We could go about trying to move the load/ep address of that kernel but, my feeling is that's probably the wrong thing to do, we can just as easily align-down and add to the flush length. What header is this? Perhaps it should be updated to be a cache-line multiple in size? I don't think so it's a TEE header, that's pretty fixed. I suspect the impact of this patch is minimal, since people hopefully don't put data just before the image is loaded. But if they did, and the image is loaded using DMA behind the cache, we might have tricky bugs. That's why in general I'm not keen on silently messing with the cache outside the expected range. Yes, I agree with both points. How printing a warning ? if (flush_start < load) flush_len += load - flush_start; if (flush_start < load) { printf("WARNING: unaligned load address 0x%08lx flushing 0x%08lx\n", load, flush_start); flush_len += load - flush_start; } ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
Hi Bryan, On 17 April 2018 at 03:27, Bryan O'Donoghue wrote: > > > > On 16/04/18 17:49, Simon Glass wrote: >> >> On 15 April 2018 at 04:48, Bryan O'Donoghue >> wrote: >>> >>> commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") >>> aligns the end address of the cache flush operation to a cache-line size to >>> ensure lower-layers in the code accept the range provided and flush. >>> >>> A similar action should be taken for the begin address of a cache flush >>> operation. The load address may not be aligned to a cache-line boundary, so >>> ensure the passed address is aligned. >>> >>> Signed-off-by: Bryan O'Donoghue >>> Reported-by: Breno Matheus Lima >>> Suggested-by: Tom Rini >>> Cc: Simon Glass >>> --- >>> common/bootm.c | 8 +++- >>> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> >> I feel that using an unaligned start address should probably be an >> error. Why would that be useful? >> >> Apart from that: >> >> Reviewed-by: Simon Glass >> >> Regards, >> Simon >> > > We are booting a kernel that has an entry point aligned a cacheline boundary > with a header prefix/load-address that is a negative offset from that. > > We could go about trying to move the load/ep address of that kernel but, my > feeling is that's probably the wrong thing to do, we can just as easily > align-down and add to the flush length. What header is this? Perhaps it should be updated to be a cache-line multiple in size? I suspect the impact of this patch is minimal, since people hopefully don't put data just before the image is loaded. But if they did, and the image is loaded using DMA behind the cache, we might have tricky bugs. That's why in general I'm not keen on silently messing with the cache outside the expected range. Regards, Simon ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
On 16/04/18 17:49, Simon Glass wrote: On 15 April 2018 at 04:48, Bryan O'Donoghue wrote: commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") aligns the end address of the cache flush operation to a cache-line size to ensure lower-layers in the code accept the range provided and flush. A similar action should be taken for the begin address of a cache flush operation. The load address may not be aligned to a cache-line boundary, so ensure the passed address is aligned. Signed-off-by: Bryan O'Donoghue Reported-by: Breno Matheus Lima Suggested-by: Tom Rini Cc: Simon Glass --- common/bootm.c | 8 +++- 1 file changed, 7 insertions(+), 1 deletion(-) I feel that using an unaligned start address should probably be an error. Why would that be useful? Apart from that: Reviewed-by: Simon Glass Regards, Simon We are booting a kernel that has an entry point aligned a cacheline boundary with a header prefix/load-address that is a negative offset from that. We could go about trying to move the load/ep address of that kernel but, my feeling is that's probably the wrong thing to do, we can just as easily align-down and add to the flush length. --- bod ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
On 15 April 2018 at 04:48, Bryan O'Donoghue wrote: > commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") > aligns the end address of the cache flush operation to a cache-line size to > ensure lower-layers in the code accept the range provided and flush. > > A similar action should be taken for the begin address of a cache flush > operation. The load address may not be aligned to a cache-line boundary, so > ensure the passed address is aligned. > > Signed-off-by: Bryan O'Donoghue > Reported-by: Breno Matheus Lima > Suggested-by: Tom Rini > Cc: Simon Glass > --- > common/bootm.c | 8 +++- > 1 file changed, 7 insertions(+), 1 deletion(-) I feel that using an unaligned start address should probably be an error. Why would that be useful? Apart from that: Reviewed-by: Simon Glass Regards, Simon ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH v2] bootm: Align cache flush begin address
Hi Bryan, 2018-04-15 7:48 GMT-03:00 Bryan O'Donoghue : > commit b4d956f6bc0f ("bootm: Align cache flush end address correctly") > aligns the end address of the cache flush operation to a cache-line size to > ensure lower-layers in the code accept the range provided and flush. > > A similar action should be taken for the begin address of a cache flush > operation. The load address may not be aligned to a cache-line boundary, so > ensure the passed address is aligned. > > Signed-off-by: Bryan O'Donoghue > Reported-by: Breno Matheus Lima > Suggested-by: Tom Rini > Cc: Simon Glass Thanks for the fix, I'm not seeing the issue anymore. Tested-by: Breno Lima ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot